Definition: "Pool"

This uses deletion - look for words that suggest removing or taking away certain letters from other words in the clue.

"Not new" indicates you should remove the letter N from the preceding words. Look at "nude hen night" and remove N to find your answer.

Answer: EIGHT | "Pool" refers to the 8-ball in pool. "Nude hen night" gives you the letters, and "not new" means remove N, leaving you with EIGHT.