Boss has no right to make blunder (5)
I believe the answer is:
gaffe
'blunder' is the definition.
(gaffe is a kind of blunder)
'boss has no right' is the wordplay.
'boss' becomes 'gaffer' ('gaffer' can be a synonym of 'boss').
'has no' suggests deleting specific letters.
'right' becomes 'r' (common abbreviation).
'gaffer' with 'r' taken away is 'GAFFE'.
'to make' acts as a link.
(Other definitions for gaffe that I've seen before include "slip" , "embarrassing error" , "Social blunder" , "Boob" , "Indiscretion" .)