Mistakes of bosses seeing no resistance (6)
I believe the answer is:
gaffes
'mistakes' is the definition.
(I know this)
'bosses seeing no resistance' is the wordplay.
'bosses' becomes 'gaffers' (gaffer can mean a boss or supervisor).
'seeing no' is a deletion indicator.
'resistance' becomes 'r' (electronics abbreviation).
'gaffers' with 'r' taken out is 'GAFFES'.
'of' acts as a link.
(Other definitions for gaffes that I've seen before include "Faux pas" , "Socially embarrassing actions or remarks" , "bloomers" , "Embarrassing blunders" , "Social blunders, often of speech" .)