principal

[1]	school principal , head teacher , head
[2]	star , owner , proprietor , lead , chairman , chairwoman , chairperson , (managing) director , head , president , chief , chief executive officer , CEO , manager/(Brit) manageress , superintendent , supervisor , (Colloq) boss , (US) (head/chief) honcho
[3]	dean , corpus , principal sum , director , (Mainly Brit) headmaster , headmistress , master , rector , (vice-)chancellor
[4]	(working) capital , capital funds , resources , investment , backing , (cash) reserve(s) , assets , money
[5]	star , dealer , lead , heroine , hero , leading lady/man , leading role , main part , diva , premiere danseuse , premier danseur , prima donna , prima ballerina

adj.

[1]	chief , primary , prime , paramount , main , first , foremost , ranking , pre-eminent , predominant , dominant , prevailing , leading , starring
[2]	important , prominent , leading , key , cardinal
[3]	chief , main , primary , master