Suffering after picking up undergarment with an arachnid (10)
I believe the answer is:
harvestman
'an arachnid' is the definition.
(harvestman is a kind of arachnid)
'suffering after picking up undergarment' is the wordplay.
I cannot really see how this works, but
'undergarment' could be 'vest' (vest is a kind of undergarment) and 'vest' is present in the answer.
The remaining letters 'harman' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
'with' acts as a link.
Can you help me to learn more?
(Other definitions for harvestman that I've seen before include "one gathers" , "It's an arachnid" .)