All ad hoc synonyms

adj ad hoc

• impromptu — made or done without previous preparation: an impromptu address to the unexpected crowds.
• provisional — providing or serving for the time being only; existing only until permanently or properly replaced; temporary: a provisional government.
• special — of a distinct or particular kind or character: a special kind of key.
• specific — having a special application, bearing, or reference; specifying, explicit, or definite: to state one's specific purpose.
• specified — to mention or name specifically or definitely; state in detail: He did not specify the amount needed.