offhand

Synonyms: aloof breezy brusque casual cavalier cool curt easygoing folksy glib informal laid-back mellow perfunctory unceremonious unconcerned uninterested

Antonyms: calculated careful considered deliberate planned

Synonyms: extemporary extempore impromptu improvised informal off the cuff off the hip off the top of head spontaneous spur-of-the-moment throwaway unpremeditated unprepared unrehearsed unstudied without preparation

Antonyms: planned practiced