Synonyms of ad hoc

Adjective

1. ad hoc, unplanned (vs. planned)

usage: often improvised or impromptu; "an ad hoc committee meeting"

2. ad hoc, specific (vs. general) (vs. nonspecific)

usage: for or concerned with one specific purpose; "a coordinated policy instead of ad hoc decisions"

Adverb

1. ad hoc

usage: for one specific case; "they were appointed ad hoc"