Youth spilling green tea (8)
I believe the answer is:
teenager
'youth' is the definition.
(thesaurus)
'spilling green tea' is the wordplay.
'spilling' indicates anagramming the letters.
'green'+'tea'='greentea'
'greentea' is an anagram of 'TEENAGER'.
(Other definitions for teenager that I've seen before include "Young person" , "one no longer twelve?" , "Youngster" , "one with an unpredictable nature" , "hormonal problem?" .)