Card played by old unforgiving legislator (5)
I believe the answer is:
draco
'unforgiving legislator' is the definition.
'draco' can be an answer for 'legislator' (I've seen this before). I'm not certain of the 'unforgiving' bit.
'card played by old' is the wordplay.
'played' indicates anagramming the letters (letters playing around).
'by' says to put letters next to each other.
'old' becomes 'o' (abbreviation).
'card' anagrammed gives 'drac'.
'drac'+'o'='DRACO'
Can you help me to learn more?
(Other definitions for draco that I've seen before include "Athenian lawmaker" , "Constellation, the Dragon" , "Ruthless lawmaker" , "death-dealing lawman" , "archon" .)