Female having to carry oxygen pump (4)
I believe the answer is:
shoe
'pump' is the definition.
(I've seen this in another clue)
'female having to carry oxygen' is the wordplay.
I cannot quite understand how this works, but
'oxygen' could be 'o' (atomic symbol for oxygen) and 'o' is located in the answer.
'female' could be 'she' ('she' refers to a woman) and 'she' is located in the leftover letters.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for shoe that I've seen before include "Foot-covering" , "Covering for foot" , "9 maybe" , "Winkle-picker, for example" , "Maybe casual" .)