Bend in river is more tight around delta (7)
I believe the answer is:
meander
'bend in river' is the definition.
'meander' can be an answer for 'bend' (thesaurus). I am unsure of the 'in river' bit.
'more tight around delta' is the wordplay.
'more tight' becomes 'meaner' ('mean' can be a synonym of 'tight').
'around' is an insertion indicator.
'delta' becomes 'd' (phonetic alphabet: alpha, bravo, charlie etc.).
'meaner' placed around 'd' is 'MEANDER'.
'is' acts as a link.
Can you help me to learn more?
(Other definitions for meander that I've seen before include "windy" , "Wander in leisurely way, like stream" , "Dear men (anag) - wander" , "Wander aimlessly like a stream" , "Wind (like a river)" .)