Male, having no heart about middle of 60s, was intimidating (8)
I believe the answer is:
hectored
'intimidating' is the definition.
The answer and definition are different parts of speech. However, past participle verbs and adjectives can occasionally mean the same thing.
'male having no heart about middle of 60s' is the wordplay.
'male' becomes 'he'.
'having no heart' becomes 'cored' (I can't explain this - if you can you should believe this answer much more).
'about' is an insertion indicator.
'middle of' says to take the centre.
'60s' becomes 'sixties' ('sixty' can be a synonym of '60').
The central letter of 'sixties' is 't'.
'cored' placed around 't' is 'ctored'.
'he'+'ctored'='HECTORED'
'was' is the link.
Can you help me to learn more?
(Other definitions for hectored that I've seen before include "Annoyed" , "Intimidated, bullied" , "Talked to bullyingly" , "Bullied; blustered" .)