Antonyms for Reduce | Reduce at Open Dictionary of English by LearnThat Foundation

Antonyms for Reduce (opposite meaning)

WordNet sense 1 (add details, as to an account or idea; clarify the meaning of and discourse in a learned way, usually in writing):

expand

WordNet sense 2 (make large):

blow up

WordNet sense 3 (add oxygen to or combine with oxygen):

oxidize, oxidise

WordNet sense 4 (increase (one's body weight)):

gain

From the ODE community, based on WordNetadd/edit