One of seven slightly intoxicated (5)
I believe the answer is:
happy
'intoxicated' is the definition.
(thesaurus)
I don't understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for happy that I've seen before include "Cheerful - dwarf" , "Carefree" , "Fortunate; content" , "Pleased; fortunate" , "Well-pleased" .)