commer

An obsolete verb, now completely out of use, meaning to compare or put things side by side — derived from comme ("like, as") plus the -er ending. Recorded in 16th-century texts; it survives only in dictionaries of old and dialectal French, not in any modern usage.

• Si je ne comme bien, qu'un autre comme mieux pour moi. — If I don't compare well, let another compare better for me (a 16th-century example).
• Ce mot ancien, commer, signifiait comparer. — This old word, commer, meant "to compare."
• On ne trouve plus commer que dans les dictionnaires historiques. — Commer is now found only in historical dictionaries.

There's no real modern mistake to flag since commer is dead vocabulary — the one genuine trap is confusing it with commercer or commérer, which look similar but have completely different, still-current meanings.

Often confused with comparer.