This person's on tram stoned, excited and showing off? (13)
I believe the answer is:
demonstrative
'showing off?' is the definition.
'this person's on tram stoned excited' is the wordplay.
'this person's' becomes 'ive' (as in 'I've', referring to the crossword setter).
'on' says to put letters next to each other.
'excited' indicates anagramming the letters.
'tram'+'stoned'='tramstoned'
'tramstoned' anagrammed gives 'demonstrat'.
'ive' put after 'demonstrat' is 'DEMONSTRATIVE'.
'and' is the link.
(Other definitions for demonstrative that I've seen before include "Showing feelings freely" , "Unrestrained in showing feelings" , "Given to expressing one's feelings" , "Tending to open display of feelings" , "Gushing" .)