One constantly flattering the aged -- a Leo? (3-5)

'one constantly flattering the aged a leo?' is the definition.
I can't judge whether this defines the answer.

'one constantly flattering the aged' is the wordplay.
I cannot quite see how this works, but
'one' could be 'a' (a thing is one thing) and 'a' is found within the answer.
an anagram of 'the' is 'eth' which is within the remaining letters.
an anagram of 'aged' is 'gead' which is present in the left over letters.
No letters remain.
This explanation may well be incorrect...

Can you help me to learn more?