Phone engineer around noon (4)
I believe the answer is:
ring
'phone' is the definition.
('ring' can be a synonym of 'phone')
'engineer around noon' is the wordplay.
'engineer' becomes 'rig' (I've seen this before).
'around' is an insertion indicator.
'noon' becomes 'n'.
'rig' enclosing 'n' is 'RING'.
(Other definitions for ring that I've seen before include "Contact" , "Circle; telephone" , "Make sound like phone" , "something at the jewellery shop?" , "Toll" .)