Robust line in figurative expression that hurts (7)
I believe the answer is:
towrope
'robust line' is the definition.
'towrope' can be an answer for 'line' (towrope is a kind of line). I am unsure of the 'robust' bit.
'in figurative expression that hurts' is the wordplay.
'in' means one lot of letters goes inside another.
'figurative expression' becomes 'trope' (I've seen this in another clue).
'that hurts' becomes 'ow!'.
'trope' placed around 'ow' is 'TOWROPE'.
Can you help me to learn more?
(Other definitions for towrope that I've seen before include "Cable for hauling vehicle or vessel" , "AA might assist with this" , "What may pull broken-down vehicle" , "Pulling cable" , "Cable used after breakdowns" .)