Blunder beginning to ruin boss (6)

I believe the answer is:

gaffer

'boss' is the definition.
(I know that boss can be written as gaffer)

'blunder beginning to ruin' is the wordplay.
'blunder' becomes 'gaffe' (gaffe is a kind of blunder).
'beginning to' suggests taking the first letters.
The first letter of 'ruin' is 'r'.
'gaffe'+'r'='GAFFER'

(Other definitions for gaffer that I've seen before include "Boss, overseer" , "Superior" , "blunderer" , "Supervisor; chief electrician" , "Informal boss or foreman" .)

I've seen this clue in The Telegraph.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.