Emily Dickinson Lexicon

LUKE'WARM, a. [Sax. vlaco, tepid, moderately warm; vlacian, to warm; D. laauw, laauwen; G. lau; Dan. lunken, lukewarm; lunker, to make tepid; allied to flag, lag, or to lay, allay, or to slack.]

1. Moderately warm; tepid; as, lukewarm water; lukewarm beat. – Wiseman. Newton.
2. Not ardent; not zealous; cool; indifferent; as, lukewarm obedience; lukewarm patriots. – Rev. iii. Dryden. Addison.