Mark bored by Liberal, a notorious hard-liner (6)
I believe the answer is:
stalin
'a notorious hard-liner' is the definition.
The definition and answer can be both people as well as being singular nouns.
Perhaps there's a link between them I don't understand?
'mark bored by liberal' is the wordplay.
I cannot really see how this works, but
'liberal' could be 'l' (abbreviation) and 'l' is present in the answer.
'mark' could be 'stain' (synonyms) and 'stain' is found in the leftover letters.
No letters remain.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for stalin that I've seen before include "Russian WW2 dictator" , "Joseph -, Russian World War two dictator" , "Russian tyrant" , "Communist dictator" , "Tyrant - last in (anag)" .)