Call that's close -- nothing in it (5)
I believe the answer is:
shout
'call' is the definition.
('shout' can be a synonym of 'call')
'close nothing in it' is the wordplay.
'close' becomes 'shut' ('shut' can be a synonym of 'close'**).
'nothing' becomes 'o' (looks like zero - 0).
'in it' indicates putting letters inside.
'shut' enclosing 'o' is 'SHOUT'.
'that's' acts as a link.
(Other definitions for shout that I've seen before include "Noise" , "(Statement) with opposite sense intended" , "bellow" , "Bawl" , "Call loudly" .)