Eccentric pal meets raging mob with coolness (6)
I believe the answer is:
aplomb
'coolness' is the definition.
(I've seen this before)
'eccentric pal meets raging mob' is the wordplay.
'eccentric' indicates anagramming the letters.
'meets' says to put letters next to each other.
'raging' indicates an anagram.
'pal' is an anagram of 'apl'.
'mob' is an anagram of 'omb'.
'apl'+'omb'='APLOMB'
'with' is the link.
(Other definitions for aplomb that I've seen before include "Nonchalant confidence" , "Self-satisfied poise" , "Self-satisfied dignity and confidence" , "Self-satisfied assurance" , "'Poise, sang-froid (6)'" .)