Off the top of one's head and Spur-of-the-moment

Spur-of-the-moment and off the top of one's head are semantically related. In some cases you can use "Spur-of-the-moment" instead an adjective phrase "Off the top of one's head".

Spur-of-the-moment adjective - Made or done without previous thought or preparation.

Off the top of one's head and spur-of-the-moment are semantically related. You can use "Off the top of one's head" instead an adjective phrase "Spur-of-the-moment".