A reason for being stranded? (7)
I believe the answer is:
aground
'being stranded?' is the definition.
(similar in meaning)
'a reason' is the wordplay.
'reason' becomes 'ground' (synonyms).
'a'+'ground'='AGROUND'
'for' is the link.
(Other definitions for aground that I've seen before include "No longer floating" , "on rocks, perhaps" , "(Of ship) not floating" , "Beached" , "out of water" .)