As entertainment, it could be somewhat flimsy (4)
I believe the answer is:
film
'as entertainment it' is the definition.
I can't tell whether this defines the answer.
'be somewhat flimsy' is the wordplay.
'be' becomes 'fit' (fitting is a kind of being).
'somewhat' means to remove the last letter (some but not all of the word).
'flimsy' becomes 'lm' (I can't justify this - if you can you should believe this answer much more).
'fit' with its final letter taken away is 'fi'.
'fi'+'lm'='FILM'
'could' is the link.
Can you help me to learn more?
(Other definitions for film that I've seen before include "Thin coating for movie." , "Motion picture" , "Veil; cinema attraction" , "Skin" , "Screen" .)