Poet left this in the way (5)
I believe the answer is:
plath
'poet' is the definition.
(I know that Plath is a poet)
'left this in the way' is the wordplay.
'left' becomes 'l' (common abbreviation).
'this in the' means one lot of letters goes inside another.
'way' becomes 'path' (synonyms).
'l' going inside 'path' is 'PLATH'.
(Other definitions for plath that I've seen before include "See 17" , "Sylvia -, US poet, married Ted Hughes" , "Sylvia --, American poet" .)