Shouts lines in agreement (5)
I believe the answer is:
yells
'shouts' is the definition.
('yell' can be a synonym of 'shout')
'lines in agreement' is the wordplay.
'lines' becomes 'll' (I've seen this in other clues).
'in' indicates putting letters inside.
'agreement' becomes 'yes'.
'll' put into 'yes' is 'YELLS'.
(Other definitions for yells that I've seen before include "Screams" , "Shouts loudly" , "Cries out" .)