Strike a companion as being a snag (5)
I believe the answer is:
hitch
'a snag' is the definition.
('hitch' can be a synonym of 'snag')
'strike a companion' is the wordplay.
'strike' becomes 'hit' ('hit' can be a synonym of 'strike'**).
'a companion' becomes 'ch' (I've seen this in other clues).
'hit'+'ch'='HITCH'
'as being' 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 hitch that I've seen before include "Jerk" , "Setback" , "something uplifting" , "get a free ride" , "Hindrance" .)