Boss with certain way of working to absorb pressure (7)
I believe the answer is:
supremo
'boss' is the definition.
(I've seen this before)
'certain way of working to absorb pressure' is the wordplay.
'certain' becomes 'sure' (synonyms).
'way of working' becomes 'mo' (abbreviation for modus operandi).
'to absorb' is an insertion indicator.
'pressure' becomes 'p' (abbreviation).
'sure'+'mo'='suremo'
'suremo' placed around 'p' is 'SUPREMO'.
'with' is the link.
(Other definitions for supremo that I've seen before include "big Daddy" , "Top dog" , "Leader with unlimited powers" , "Person invested with great authority" , "Champion" .)