One not dressed for digging? (4)
I believe the answer is:
into
'digging?' is the definition.
(to dig something is to appreciate it or be into it)
'one not dressed' is the wordplay.
'one' becomes 'i' (Roman numeral).
'dressed' indicates an anagram ('dress' can mean 'prepare').
'not' anagrammed gives 'nto'.
'i'+'nto'='INTO'
'for' acts as a link.
(Other definitions for into that I've seen before include "Not I (anag.)" , "A fan of" , "Curious about" , "ignition regularly missing" , "Showing enthusiasm for" .)