Pick up smell, perhaps (5)
I believe the answer is:
sense
This clue is a double definition.
'pick up' is the first definition.
('sense' can be a synonym of 'pick up')
'smell perhaps' is the second definition.
(smell is a kind of sense)
(Other definitions for sense that I've seen before include "Reason; perceive" , "Logic" , "Eg, sight, smell" , "Sat lazily; hung loosely" , "Nous" .)