Longman Dictionary of Contemporary English
Wiktionary
a. 1 Not scripted; without a script. 2 (label en by extension) unplanned, unexpected, spontaneous.
WordNet
adj. not furnished with or using a script; "unrehearsed and unscript spot interviews"; "unscripted talk shows" [ant: scripted]
Wikipedia
Unscripted is an American comedy-drama series that aired on HBO in early 2005. Its title referred to the fact that the series was largely improvised by its performers. The series was executive produced by Steven Soderbergh, George Clooney, and Grant Heslov.
Usage examples of "unscripted".
Drake, and, at the sound of the famous fictional movie line echoing in the relevant air of this real place, they both laughed, the levels of self-consciousness attendant upon a contemporary journey like this were positively Piranesian in number and involution, the pertinent dialogue had already been spoken, the images already photographed, the unsullied, unscripted experience was practically extinct, and you were left to wander at best through a familiar maze of distorting mirrors -- unless somewhere up ahead the living coils of this river carried one down and out of the fun house.
We then went 'live' and unscripted - and usually alone - into a very small studio where we ourselves placed the computerised weather symbols on the background screen map of Britain.