Company boss takes all morning for brief appearance (5)
I believe the answer is:
cameo
'brief appearance' is the definition.
(brief appearance in a film)
'company boss takes all morning' is the wordplay.
'company boss' becomes 'CEO' (chief executive officer).
'takes' indicates putting letters inside.
'all morning' becomes 'am' (this might be a standard abbreviation which I don't know about).
'ceo' going around 'am' is 'CAMEO'.
'for' is the link.
Can you help me to learn more?
(Other definitions for cameo that I've seen before include "Something small but well executed, say role in play" , "Brief role" , "Carving in relief, on a brooch say" , "Small role - gem with a figure carved in relief" , "Miniature picture" .)