Cross retrograde art and poetry (8)
I believe the answer is:
traverse
'cross' is the definition.
(I know that cross can be written as traverse)
'retrograde art and poetry' is the wordplay.
'retrograde' is a reversal indicator.
'and' says to put letters next to each other.
'poetry' becomes 'verse' (synonyms).
'art' back-to-front is 'tra'.
'tra'+'verse'='TRAVERSE'
(Other definitions for traverse that I've seen before include "Ski diagonally across (a slope)" , "Travel across or pass over" , "cover" , "Move across" , "Cross sideways" .)