Question — shoe (4)
I believe the answer is:
pump
I believe this is a double definition.
'question' is the first definition.
(I know that pump is a more specific form of the action question)
'shoe' is the second definition.
(I know that Pump is a pump)
(Other definitions for pump that I've seen before include "Flat shoe; siphon" , "Compressor, light shoe" , "The heart is one" , "ask a lot of questions" , "Fluid moving device" .)