Large crowd up for exciting tournament (5,3)
I believe the answer is:
world cup
'tournament' is the definition.
(I've seen this before)
'large crowd up for exciting' is the wordplay.
'large' becomes 'l'.
'for exciting' indicates anagramming the letters (letters must be stimulated or excited).
'l'+'crowd'+'up'='lcrowdup'
'lcrowdup' is an anagram of 'WORLD CUP'.
(Other definitions for world cup that I've seen before include "sporting event" , "football competition" , "Soccer tournament organised every four years by FIFA" .)