A pine prop somewhere on the coast? (10)

I believe the answer is:

alongshore

'somewhere on the coast?' is the definition.
(along the coast)

'a pine prop' is the wordplay.
'pine' becomes 'long' (synonyms).
'prop' becomes 'shore' (shore can mean to prop up or support).
'a'+'long'+'shore'='ALONGSHORE'

(Another definition for alongshore that I've seen is " by the side of the sea".)

I've seen this clue in The Times.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.