Play hockey without energy - it feels stifling (5)
I believe the answer is:
choky
'stifling' is the definition.
(I've seen this before)
'play hockey without energy' is the wordplay.
'play' indicates anagramming the letters.
'without' suggests deleting specific letters.
'energy' becomes 'e' (physics symbol as in E=mc2).
'hockey' with 'e' taken out is 'hocky'.
'hocky' is an anagram of 'CHOKY'.
'it feels' is the link.
I am not very happy about this link. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for choky that I've seen before include "Jug" , "tending to block up" , "Stifling" , "prison" .)