Squeeze fifty in temporary quarters (5)
I believe the answer is:
clamp
'squeeze' is the definition.
(I've seen this in another clue)
'fifty in temporary quarters' is the wordplay.
'fifty' becomes 'L' (Roman numeral).
'in' means one lot of letters goes inside another.
'temporary quarters' becomes 'camp' (place where people stay temporarily).
'l' put into 'camp' is 'CLAMP'.
(Other definitions for clamp that I've seen before include "Securing device with movable jaws" , "Grip firmly" , "device to hold" , "Pile of bricks" , "Brace for holding something in place" .)