Vulnerable gran needed fluid (10)
I believe the answer is:
endangered
'vulnerable' is the definition.
('endangered' can be similar in meaning to 'vulnerable')
'gran needed fluid' is the wordplay.
'fluid' indicates an anagram.
'gran'+'needed'='granneeded'
'granneeded' anagrammed gives 'ENDANGERED'.
(Other definitions for endangered that I've seen before include "put at risk" , "Threatened" , "compromised" , "exposed to risk" , "Vulnerable" .)