Argument having value for the poet (10)
I believe the answer is:
wordsworth
'the poet' is the definition.
(William Wordsworth, 1770-1850)
'argument having value' is the wordplay.
'argument' becomes 'words' (to have words with someone is to argue with them).
'having' means one lot of letters go next to another.
'value' becomes 'worth' (I've seen this before).
'words'+'worth'='WORDSWORTH'
'for' is the link.
(Other definitions for wordsworth that I've seen before include "Romantic poet" , "writer" , "Poet (of the 20s)" .)