Pretending an attack, knocks out a giant with fine moves (8)
I believe the answer is:
feinting
'pretending an attack' is the definition.
(I've seen this before)
'giant with fine moves' is the wordplay.
'giant' becomes 'ting' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'with' says to put letters next to each other.
'moves' indicates an anagram.
'fine' with letters rearranged gives 'fein'.
'ting' put after 'fein' is 'FEINTING'.
'knocks out a' acts as a link.
This may not be correct. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for feinting that I've seen before include "Making a deceptive move" , "Pretending an attack" .)