Poet composed sonnet about New York (8)
I believe the answer is:
tennyson
'poet' is the definition.
(I've seen this before)
'composed sonnet about new york' is the wordplay.
'composed' indicates an anagram.
'about' indicates putting letters inside.
'new york' becomes 'ny'.
'sonnet' anagrammed gives 'tenson'.
'tenson' placed around 'ny' is 'TENNYSON'.
(Other definitions for tennyson that I've seen before include "Alfred Lord . . . . . . . . great poet of 'The Lady of Shalott'" , "linesman" , "English Victorian poet" , "Alfred, Lord -, nineteenth century Poet Laureate" , "Alfred -, English poet (In Memoriam)" .)