"A lazy cook does not cook."
Translation:Coquus ignavus non coquit.
Do we have a system in place for if the cook is a woman? Like, Romans tend to use feminine adjectives with 1st declension masculine nouns like poeta to let you know "hey I'm actually talking about a woman poet," but when it's a second declension noun how would you express that? For this one in particular, coqua should probably be accepted though (it's in Plautus).
Poeta is not to say "hey, I'm actually a woman poet", like in Spanish, it's "poeta", and it has no link with the ability to be a woman, it's only the form, probably the evolution of the sound from the ancient Greek ποιητής, poiêtếs.
The "a" ending is not always feminine, as the plural of neutral nouns with -um is with -a.
Coqua is the feminine of Coquus.
Upshot: coqua should be accepted: "Coqua ignava non coquit". For the rest: let me rephrase because I agree with everything else you said (except I'll take your word on the Spanish). If the Latin word denoting a profession happens to be 2nd declension and doesn't have an attested 1st declension equivalent, what do you do to show it's actually a woman? "Noun-us adjectiv-a" is my gut instinct.
It makes sense with the French poète for a male, and poétesse for a female. And poetess also exist in English, borrowed from "poétesse".
Poète/Poétesse did exist since very old forms in old French.
The dictionary "Trésor de la langue française" tells us that "poétesse" is from medieval Latin (so not classical Latin like this course) "poetissa".