1. moderately warm

- he hates lukewarm coffee

Similar word(s): warm, tepid

2. feeling or showing little interest or enthusiasm

- gave only lukewarm support to the candidate

Similar word(s): unenthusiastic, halfhearted, tepid

Sentences with lukewarm as an adjective:

- Wash it in lukewarm water.

- The suggestion met with only a lukewarm response.