Synonyms and related words :
Laodicean, bland, changeable, cold, cool, fervorless, indecisive, indifferent, infirm of purpose, infirm of will, insipid, irresolute, lukewarm, milk-and-water, milky, mushy, neuter, neutral, perfunctory, tasteless, tepid, unenthusiastic, vapid, watery, wishy-washy, zealless