Intimidating blokes acting out of turn to begin with (8)
I believe the answer is:
menacing
'intimidating' is the definition.
(I've seen this before)
'blokes acting out of turn to begin with' is the wordplay.
'blokes' becomes 'men' (bloke can informally mean a man).
'acting out of turn' becomes 'acing' (I can't justify this - if you can you should give a lot more credence to this answer).
'to begin with' means one lot of letters go next to another.
'men'+'acing'='MENACING'
Can you help me to learn more?
(Other definitions for menacing that I've seen before include "Intimidating" , "Threatening" , "Ominous" , "Suggesting danger" , "Scary" .)