The handakuten, which indicates that a kana with an initial of h- should be pronounced with p- (i.e. ha with a handakuten is pronounced as pa). It is also sometimes used with k- kana to indicate ng- (a phoneme that is usually an allophone of /g/).

antinuclear

(physics) an antiparticle

antonym

range, region / area, field, sphere / domain, territory

derive the kana for a mora onsetted with /p/ from the kana for a mora onsetted with /h/

objection, rebuttal, refutation

(typography) typesetting or composition

(typography) to typeset or compose

resistance, defiance, disobedience