The Oxford Thesaurus An A-Z Dictionary of Synonyms - lukewarmadj.

1) tepid, room temperature, warm: I like my bath-water lukewarm. 2) cool, indifferent, half-hearted, chill, chilly, phlegmatic, unresponsive, unenthusiastic, nonchalant, lackadaisical, apathetic, insouciant, Laodicean, unmoved, US half-baked, Colloq laid-back: My ideas for improving efficiency continued to receive a lukewarm reception from the board.