taken unawares (?.)
- ad-lib
- astonished
- caught napping
- caught off balance
- caught short
- extemporaneous
- extemporized
- haphazard
- hasty
- impromptu
- improvised
- makeshift
- precipitate
- rough-and-ready
- snap
- struck with surprise
- surprised
- taken aback
- taken by surprise
- tripped up
- unarranged
- unbegun
- unconcocted
- uncontrived
- undeliberated
- undevised
- unhatched
- unmade
- unmanufactured
- unorganized
- unplanned
- unpremeditated
- unprepared
- unprimed
- unready
- unstudied
