Clue: Good for Porthos beginning to kick something large in novel (10)
Answer: BONKBUSTER
Explanation: Definition: novel

**BON** ("good" in French, and Porthos (one of the Three Musketeers) was French) + [*beginning to*] **K**(ick) + **BUSTER **("something large" in American English)
 
*A bonkbuster is a novel which contains a number of sexual encounters, often portrayed in graphic detail (eg *Fifty Shades of Grey*)