Put the wind up a member crossing lake (5)
I believe the answer is:
alarm
'put the wind up' is the definition.
(I've seen this before)
'a member crossing lake' is the wordplay.
'member' becomes 'arm' (arm is a kind of member).
'crossing' is an insertion indicator.
'lake' becomes 'l'.
'a'+'arm'='aarm'
'aarm' going around 'l' is 'ALARM'.
(Other definitions for alarm that I've seen before include "Put the wind up" , "Device sounding danger" , "Warning bell" , "Agitate" , "Scare with warning device" .)