(linguistics) In violation of one or more of the rules and conventions of a language as defined by the grammar, resulting in unacceptable or incorrect usage.

(biochemistry) Any one of a group of enzymes that produce bioluminescence by oxidizing luciferin.

(slang, sometimes used attributively) A male hipster who affects a rugged, outdoorsy look, typified by plaid shirts and a full beard.

A surname.