Stranded guard on manoeuvres (7)
I believe the answer is:
aground
'stranded' is the definition.
('aground' can be similar in meaning to 'stranded')
'guard on manoeuvres' is the wordplay.
'manoeuvres' indicates anagramming the letters.
'guard'+'on'='guardon'
'guardon' is an anagram of 'AGROUND'.
(Other definitions for aground that I've seen before include "(Ship) unable to float" , "On guard (anag.)" , "on the bed" , "High and dry" , "(Of ship) touching the bottom" .)