Burden almost overwhelms Catholic poet (5)
I believe the answer is:
lorca
'poet' is the definition.
(I know this)
'burden almost overwhelms catholic' is the wordplay.
'burden' becomes 'load' (synonyms).
'almost' means to remove the last letter (most of the word but not all of it).
'overwhelms' means one lot of letters goes inside another.
'catholic' becomes 'RC' (Roman Catholic).
'load' with its last letter taken away is 'loa'.
'loa' placed around 'rc' is 'LORCA'.
(Other definitions for lorca that I've seen before include "poet from Spain" , "Federico Garcia -, twentieth century Spanish poet/playwright" , "Spanish writer" , "Playwright" , "Federico Garc'a-, Sp. poet; carol (anag.)" .)