Lukewarm is a word that's well known, even if it's not widely used. The term denotes one of two sentiments, "moderately warm, tepid" or "lacking conviction, halfhearted". ... This had led some etymologists to link lukewarm to the Old English word hleowe, which means "warm".

What it means to be lukewarm?

moderately warm; tepid. having or showing little ardor, zeal, or enthusiasm; indifferent: lukewarm applause.

What is the mean of lukewarm water?

Something, especially a liquid, that is lukewarm is only slightly warm. Wash your face with lukewarm water. The coffee was weak and lukewarm. Synonyms: tepid, warm, blood-warm More Synonyms of lukewarm.