How to say "based" in Latin (and the difficulties of translating modern terms into ancient languages).
After a long meditation and a lot of research, I have finally been able to determine how to translate the term "based" in Latin while preserving (1) the same denotation it has in everyday English usage and (2) good classical and idiomatic Latin.
Why is the literal translation not enough? If out of curiosity you use some translator or chatgpt to translate "based" in Latin, you will probably get the adjective "fundatus", which is the literal translation of "based" from the verb "fundare", which means, precisely, "to base" BUT in the sense of "laying the foundation of a construction". You could always say that you use "fundatus" in a metaphorical sense, in the same way that in the Middle Ages the scholastics began to use terms like "abstractus" and "concretus"; however, a regular reader of Latin would not understand the denotation, and in that case you should gloss the term with "so to speak" or "as we might say today". There is a better way to translate, which would allow even a first century Roman to understand the meaning of "based".
According to the Urban Dictionary, "based" designates a person who is true to himself, courageous, and does not care what others think; the opposite is, as you well know, "cringe". This is the sense we seek to maintain in Latin.
Why "sibi constans"? The Latin verb "constare" properly means "to stand, to be consistent"; it is usually used (1) with "ex" and ablative, to say that a thing is made of this or that; (2) simply, to say that something endures in time; (3) with dative, to say that something is evident to someone; (4) with dative, to say that something is convenient or congruent with something; and from here, finally, to the sense we are looking for, (4) with "sibi", the dative reflexive pronoun, to express congruence with oneself.
This last sense is well attested in the classical sources. For example, in Cicero (Cic. 1. Off. 33. 119): Ut constare in vitae perpetuitate possimus nobismetipsis, nec in ullo officio claudicare ("So that we can always be congruent with ourselves, and not falter in any duty"). From this it is easy to extract the idea that a "homo sibi constans" is someone who is congruent with himself, who always speaks and acts true to himself, who does not abandon his duty for fear of the opinion of others. In other words, a "homo sibi constans" is a based person.
With "sibi constans" we give up, unfortunately, using a simple adjective for "based" and must instead use two words; we also give up the style "infimus", i.e., popular, which "based" obviously connotes. It seems to me, however, that when translating modern slang into ancient languages it is better to keep the correct sense of the word and use idiomatic terms, rather than simplistic substitutions that unnecessarily increase the (already large number of) senses that exist in Latin. Using a idiomatic Latin term, instead, allows us to better understand the complexities of the Latin language, as well as to connect two different expressions, in two different languages, separated by two millennia, with the same idea. Be "based", my friend, be "tibi constans".