A boaster for example, first old guy, one with power (9)
I believe the answer is:
egomaniac
'a boaster' is the definition.
The definition and answer can be both people as well as being singular nouns.
Maybe there's a link between them I don't understand?
'example first old guy one with power' is the wordplay.
'example' becomes 'eg' (short for 'exempli gratia', 'for example' in Latin).
'first old' becomes 'o' (ast letter of 'old').
'guy' becomes 'man' (guy can informally mean a man).
'one' becomes 'i' (Roman numeral).
'with power' becomes 'ac' (AC is an example. I am not sure about the 'with' bit.).
'eg'+'o'+'man'+'i'+'ac'='EGOMANIAC'
'for' acts as a link.
Can you help me to learn more?
(Other definitions for egomaniac that I've seen before include "Come again (anag.)" , "who's full of himself" , "Abnormally egotistical person" , "Obsessively self-centred person" , "Highly self-absorbed person" .)