Cry from unknown Member of Parliament? (4)
I believe the answer is:
yowl
'cry' is the definition.
(yowl is a kind of cry)
'unknown member of parliament?' is the wordplay.
'unknown' becomes 'y' (algebra).
'member of parliament?' becomes 'owl' ('parliament' is the collective noun for 'owl').
'y'+'owl'='YOWL'
'from' acts as a link.
(Other definitions for yowl that I've seen before include "Wail" , "Wailing cry (not howl)" .)