Scottish hero — an expert climber? (7)
I believe the answer is:
wallace
This clue could be a double definition.
'scottish hero' is the first definition.
(William Wallace)
'an expert climber?' is the second definition.
The definition suggests a singular noun which matches the answer.
(Other definitions for wallace that I've seen before include "15 [AMERICAN] vice-president" , "Star of 'The Wrong Trousers'" , "Scottish insurgent" , "Scottish champion" , ".Robbie Burns poem 'Scots, wha hae wi' ...... bled'" .)