Gap crossed by the German wanderer (7)
I believe the answer is:
drifter
'wanderer' is the definition.
(I know that drifter is a type of wanderer)
'gap crossed by the german' is the wordplay.
'gap' becomes 'rift' (rift is a kind of gap).
'crossed by' means one lot of letters goes inside another (inserted letters are crossed or covered by others).
'the german' becomes 'der' ('the' in German).
'rift' placed inside 'der' is 'DRIFTER'.
(Other definitions for drifter that I've seen before include "one unsettled" , "Itinerant person" , "One who moves about aimlessly" , "Wanderer; fishing vessel" , "Fishing boat; wanderer" .)