Yours truly shut up network (4)
I believe the answer is:
mesh
'network' is the definition.
(synonyms)
'yours truly shut up' is the wordplay.
'yours truly' becomes 'me'.
'shut up' becomes 'sh'.
'me'+'sh'='MESH'
(Other definitions for mesh that I've seen before include "Undeviating" , "Grid, netting" , "Netting made of wire or thread" , "Engagement" , "Interlock" .)