off the top of one's head

off the top of one's head

1. Used other than with a figurative or idiomatic meaning: see off,‎ top,‎ head.
2. (idiomatic) In an extemporaneous manner; without careful thought, preparation, or investigation.

   I cannot think of any good examples off the top of my head, but give me a couple of hours and I'm sure I could come up with something.

• Usually used to characterize the manner of one's thinking or speaking.

• Often indicates a random piece of information put forth by a knowledgeable expert in the topic spoken within.

• offhandedly

• extemporize