Get up in brook (5)
I believe the answer is:
I believe this is a double definition.
'get up' is the first definition.
(to stand up from a sitting position)
'brook' is the second definition.
(I know that brook can be written as stand)
'in' acts as a link.
(Other definitions for stand that I've seen before include "partnership" , "Tolerate; rise" , "Be erect" , "remain in force" , "Sit here at a sports event" .)