Exposed to loss as goal got one's back up (10)
I believe the answer is:
endangered
'exposed' is the definition.
('endanger' can be a synonym of 'expose')
'back up' is the wordplay.
'back' becomes 'end' (I've seen this in other clues).
'up' becomes 'angered' (I can't explain this - if you can you should believe this answer much more).
'end'+'angered'='ENDANGERED'
'to loss as goal got one's' acts as a link.
This may not be right. Some or all of it may be part of another bit of the clue.
Can you help me to learn more?
(Other definitions for endangered that I've seen before include "compromised" , "Like some species" , "in a perilous situation" , "Put in jeopardy" , "exposed to risk" .)