What is another word for off the top of your head?
Pronunciation: [ˈɒf ðə tˈɒp ɒv jɔː hˈɛd] (IPA) 
Off the top of your head is commonly used to indicate that a suggestion or response is being made without much thought or preparation. There are several synonyms that can be used in place of this phrase such as on the fly, impromptu, spur of the moment, extemporaneous, ad-lib, improvised, and unprepared. When someone is asked a question and they respond without much consideration, they might say something like "I'm just going to give you an impromptu answer." Alternatively, if someone is asked to speak on a topic without much notice, they may give an ad-lib speech. No matter which synonym is used, it conveys the same idea of quick and unrehearsed thinking.
