What does “c’est aberrant” mean in French?

English “aberrant” is a clinical word: aberrant cells, aberrant behaviour. French aberrant is an everyday cry of disbelief. C’est aberrant ! means “that’s absurd,” “that’s outrageous,” landing roughly where English reaches for “insane” or “ridiculous.” It judges the situation rather than the person, and it works for anything from a price to a rule to a recipe that probably should not exist.

The cook here turns it into a running gag, stamping aberrante on every step of a tuna quiche — mustard smeared on by hand, tuna and emmental stirred straight in — so the word lands five times in a minute. Watch the agreement: une recette aberrante, un prix aberrant. Close relatives are the noun une aberration (a nonsense, a glaring error) and the milder, very French n’importe quoi.