Support end of pipe in watering-hole (4)
I believe the answer is:
bear
'support' is the definition.
(I know that support can be written as bear)
'end of pipe in watering-hole' is the wordplay.
'end of' says to take the final letters.
'in' indicates putting letters inside.
'watering hole' becomes 'bar' (watering hole can mean a drinking establishment).
The final letter of 'pipe' is 'e'.
'e' put into 'bar' is 'BEAR'.
(Other definitions for bear that I've seen before include "Situation where there are more sellers than willing buyers" , "See 13 across" , "Give birth to - large mammal" , "Beast - tolerate" , "a churlish individual" .)