1. They could handle predictable prompts and questions, but unrehearsed questions threw them.
adj
1. unrehearsed
1. with little or no preparation or forethought
e.g. his ad-lib comments showed poor judgment
an extemporaneous piano recital
an extemporary lecture
an extempore skit
an impromptu speech
offhand excuses
trying to sound offhanded and reassuring
an off-the-cuff toast
a few unrehearsed comments
Synonym: ad-lib extemporaneous extemporary extempore impromptu offhand offhanded off-the-cuff