Best fish, entirely presented without tail (5)
I believe the answer is:
ideal
'best' is the definition.
(similar in meaning)
'fish entirely presented without tail' is the wordplay.
I cannot really understand how this works, but
'fish' could be 'ide' (I've seen this in another clue) and 'ide' is found in the answer.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for ideal that I've seen before include "without a flaw" , "Cutting/stabbing weapons" , "A deli (anag.)" , "fine" , "Just right" .)