Pleasant heading off to choose climbing tool (3,4)
I believe the answer is:
ice pick
'climbing tool' is the definition.
'ice pick' can be an answer for 'tool' (ice pick is a kind of tool). I'm not certain of the 'climbing' bit.
'pleasant heading off to choose' is the wordplay.
'pleasant' becomes 'nice' (similar in meaning).
'heading off' means to remove the first letter.
'to choose' becomes 'pick' (picking is a kind of choosing).
'nice' with its initial letter removed is 'ice'.
'ice'+'pick'='ICE-PICK'
Can you help me to learn more?
(Other definitions for ice pick that I've seen before include "murder weapon?" , "Sharp tool" , "aid" , "Mountain climber's tool" , "Equipment used by high-level climbers" .)