Ad lib is one of my favourite borrowings, as it says in just two tiny words what English needs a whole sentence to express.
Ad lib (also ad-lib) derives from the Latin ad libitum, meaning ‘to (one’s) pleasure, as much as one likes’, and was originally used to indicate the points within a piece of sheet music or theatrical script where performers could exercise unrestrained freedom of self-expression.
Now we use this phrase as a synonym of the verb improvise, that is to mean ‘to speak or perform in public without preparation’.
I had to ad-lib as I’d forgotten my lines.
He ad-libbed his way through the entire speech.
Ad lib can also act as
- an adjective: Ann had always been much better at writing than speaking, so when asked to give an ad-lib speech she was completely paralysed with fear.
- an adverb: He spoke ad lib.
- and a noun: I’m sorry to say this but your ad-libs sounded anything but spontaneous.