Tight, muscular arms twisting (4)
I believe the answer is:
snug
'tight' is the definition.
(similar in meaning)
'arms twisting' is the wordplay.
'arms' becomes 'guns' (gun is a kind of arm).
'twisting' says the letters should be written backwards (letters twist back).
'guns' written backwards gives 'SNUG'.
'muscular' acts as a link.
I am not very happy about this link. It may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for snug that I've seen before include "Comfortable -- small secluded room" , "Small bar in pub - warm and comfortable" , "Comfy and cosy like bug in rug" , "Bar-parlour" , "Cosy retreat" .)