Long to get out of the T shirt (6)
I believe the answer is:
thirst
'long' is the definition.
(thirst can mean to long or yearn for something)
'out of the t shirt' is the wordplay.
'out of' is an anagram indicator.
't'+'shirt'='tshirt'
'tshirt' with letters rearranged gives 'THIRST'.
'to get' is the link.
(Other definitions for thirst that I've seen before include "Strong desire for drink" , "drought" , "Dryness" , "A craving for drink or knowledge" , "Hunger" .)