The trouble with language is that it can’t be trusted.
No matter what we do, it still ends up betraying us.
There are tensions in any language as there are in any human group. Structure is never stable. Relationships are never to be fully trusted. Synonyms are never perfect, the rules are never binding, exceptions are the rule, which makes everything unruly.
There are false roots, false dichotomies, false equivalences, false readings, false translations, false positives. There are false friends.
The concept of false friendship was introduced in linguistics in 1928. The idea had been known for centuries, though. The suspicion of perfidy occurring in words sounding or spelled similarly in two or more languages is an effect of etymology and linguistic evolution.
Words collide but fail to evolve in a similar fashion. Languages that are part of the same broad family, like English and French, may have a distant kinship, but use, that is use in time and space and groups, alienate them from each other.
Take money and the French word monnaie, which actually means coin. Both hark back to the Latin moneta, via the Old French word moneie. While the French monnaie evolved to mean a piece of tangible coin money, like the modern ‘pièce de monnaie’, the English money acquired an abstract, general meaning. To translate one through the other would be incorrect.
Friendship goes only this far.