Crossword Genius

Damage shoreline heartlessly (4)

Ross

I believe the answer is:

cost

Here is my best explanation:

'damage' is the definition.
(thesaurus)

'shoreline heartlessly' is the wordplay.
'shoreline' becomes 'coast' (I've seen this before).
'heartlessly' means to remove the middle letters.
'coast' with its centre removed is 'COST'.

This clue was last seen in The Telegraph