The noun Goddam is used to designate an Englishman.

This noun occurs in particular in Saint Joan: a Chronicle Play in Six Scenes and an Epilogue (New York: Brentano’s, 1924), by the Irish playwright, critic, polemicist and political activist George Bernard Shaw (1856-1950)—for example in the following two passages:

La Hire. She has made her way from Champagne with half a dozen men through the thick of everything: Burgundians, Goddams, deserters, robbers, and Lord knows who.
[…]
Joan. Jack: the world is too wicked for me. If the goddams and the Burgundians do not make an end of me, the French will.

This use of Goddam originated among the French, from the fact that they regarded the exclamation God damn as characteristic of the English—as illustrated by the following passages from two French texts:

1-: From a letter published in L’Observateur français à Londres, ou Lettres sur l’état présent de l’Angleterre, relativement à ses forces, à son commerce & à ses mœurs (London – also Paris: Merlin, bookseller, 1769), by the French author and journalist Augustin-Pierre Damiens de Gomicourt (1723-1790):

LÈTRE [sic] XLI.
A Londres, ce 1768.
Il faut convenir, Monsieur, que l’animosité des Anglais contre les Français est moins forte présentement, du moins en aparence [sic], qu’elle ne l’était autrefois. Un Français dans les rues de Londres ne s’entend plus saluer à tout moment d’un God-damn Dieu vous dane [sic], ni ne se voit plus à chaque pas apostrophé d’un French dog chien de Français.
          translation:
LETTER XLI.
In London, this 1768.
It must be admitted, Sir, that the animosity of the English towards the French is less strong at present, at least apparently, than it used to be. A Frenchman in the streets of London is no longer greeted at any moment with a God-damn, nor is he any longer at every step shouted at with a French dog.

2– : From La Folle Journée, ou Le Mariage de Figaro, Comédie en cinq Actes, en Prose (Paris: Chez Ruault, 1785), by the French playwright Pierre Augustin Caron de Beaumarchais (1732-1799): 115-116

Le Comte. Tu ne sais pas l’anglais.
Figaro. Je sais God-dam.
Le Comte. Je n’entens pas.
Figaro. Je dis que je sais God-dam.
Le Comte. Hé bien ?
Figaro. Diable ! c’est une belle langue que l’anglais ; il en faut peu pour aller loin. Avec God-dam en Angleterre, on ne manque de rien nulle part.—Voulez-vous tâter d’un bon poulet gras ? entrez dans une taverne, & faites seulement ce geste au garçon. (Il tourne la broche,) God-dam ! on vous apporte un pied de bœuf salé sans pain. C’est admirable ! Aimez-vous à boire un coup d’excellent Bourgogne ou de Clairet ? rien que celui-ci. (Il débouche une bouteille,) God-dam ! on vous sert un pot de bierre, en bel étain, la mousse aux bords. Quelle satisfaction ! Rencontrez-vous une de ces jolies personnes, qui vont trottant menu, les yeux baissés, coudes en arrière, & tortillant un peu des hanches ? mettez mignardement tous les doigts unis sur la bouche. Ah ! God-dam ! elle vous sangle un soufflet de crocheteur. Preuve qu’elle entend. Les Anglais, à la vérité, ajoutent par-ci, par-là quelques autres mots en conversant ; mais il est bien aisé de voir que God-dam est le fond de la langue.
          translation:
The Count. You don’t know any English.
Figaro. I know God-dam.
The Count. I don’t understand.
Figaro. I say that I know God-dam.
Count. What of it?
Figaro. Why! it is such a beautiful language, English; you need only a little of it to go a long way. With God-dam in England, you don’t want for anything anywhere. Do you want to taste a nice fat chicken? go into a tavern, and just make this gesture to the waiter. (He turns the pit,) God-dam! they bring you a trotter of salt beef without bread. This is admirable! Do you like to drink a glass of excellent burgundy or of claret? just this one. (He opens a bottle,) God-dam! they serve you foamy beer in a handsome pewter pot. So satisfying! Do you happen to meet one of those pretty persons, who go mincing along, eyes on the ground, elbows back, and hips lightly swaying? Delicately put all the fingers, united, on the mouth. Ah! God-dam! she straps your face with a burden-bearer’s slap. Which proves that she understands. The English, admittedly, put in a few other words here and there in conversation; but it’s very easy to see that God-dam is the basis of the language.

This French use of the noun Goddam was mentioned in British newspapers. The following, for example, is from The Morning Chronicle (London, England) of Thursday 12^th January 1804:

It cannot be denied that the English press has thrown out much contemptible abuse of the First Consul ¹; but it is nevertheless true, that with, perhaps, the whole of that the Government had no concern, and had even no controul. The abuse in France is official. The Moniteur ² of the 26^th December, contains a very long and dull Poem, entitled Goddam, in ridicule of the King and all the Princes, and many personages of rank here, both male and female. From the beginning of it we are led to think that it must have been written by some superannuated rake, for it is disgustingly obscene. The remainder is made up of very coarse abuse of the King and all the Princes, particularly the Duke of York, whose military exploits have not obtained a very partial bard.

¹ Napoléon Bonaparte (1769-1821) was the First Consul of France from December 1799 to May 1804.
² Le Moniteur Universel was then the official journal of the French government.

NOTES ON GODON

In Middle French, the noun godon was a pejorative term for an Englishman.

This noun occurs, for example, in the following French text, dated 26^th June 1432:
—as published in Actes de la Chancellerie d’Henri VI concernant la Normandie sous la domination anglaise (1422-1435) Extraits des Registres du Trésor des Chartes aux Archives Nationales (Rouen: A. Lestringant – Paris: A. Picard Fils & Cie, 1908), edited by Paul Le Cacheux:

« Que demandez vous, traistres quiens angloiz, godons plains de cervoise ? »
translation:
“What are you asking for, treacherous English dogs, godons full of beer?”

However, the noun godon may not be etymologically related to Goddam. According to the Trésor de la Langue Française informatisé, godon may be based on the onomatopoeia god-, used to call domestic animals. This onomatopoeia came to be used in nouns designating those animals (for example in gode, denoting an old ewe) and pejorative nouns designating persons (for example in godel, denoting a catamite, and in godelureau, denoting a dandy, a fop).