Antonyms of adj zealous

1 sense of zealous

Sense 1
avid, zealous -- (marked by active interest and enthusiasm; "an avid sports fan")

INDIRECT (VIA enthusiastic) -> unenthusiastic -- (not enthusiastic; lacking excitement or ardor; "an unenthusiastic performance by the orchestra"; "unenthusiastic applause")

Similarity of adj zealous

1 sense of zealous

Sense 1
avid, zealous -- (marked by active interest and enthusiasm; "an avid sports fan")
       => enthusiastic (vs. unenthusiastic) -- (having or showing great excitement and interest; "enthusiastic crowds filled the streets"; "an enthusiastic response"; "was enthusiastic about taking ballet lessons")