expression, noun-modifying (irregular)
indifferent; half-hearted; listless
Describes a person's attitude or manner as lacking enthusiasm, interest, or energy. Often used prenominally to modify nouns like 返事 (reply), 様子 (appearance), or 態度 (attitude).
See also: 気がない
彼は気のない返事をした。
He gave a half-hearted reply.
気のない様子で仕事をしている。
He's working with a listless air.
気がない is a clause meaning 'have no interest (in)' or 'not in the mood', while 気のない is the prenominal form used directly before a noun.
From 気 (spirit, mind) + の (possessive particle) + ない (not exist). Literally 'without spirit', used as a set phrase.