luke·warm 
(lkwôrm)
(lkwôrm)adj.
1. Mildly warm; tepid.
2. Lacking conviction or enthusiasm; indifferent: gave only lukewarm support to the incumbent candidate.
[Middle English leukwarm : leuk, luke (possibly alteration of leu, from Old English hlēow; see kelə-1 in the Appendix of Indo-European roots) + warm, warm; see WARM.]
lukewarmly adv.