The definition of a cockalorum is a little man who incorrectly has a very high opinion of himself.(noun)
A low-level and unimportant employee who tries to throw around his power and who thinks he is extremely important and boasts about it is an example of someone who would be described as a cockalorum.
See cockalorum in Webster's New World College Dictionary
Origin: pseudo L extension of cock; infl. by Du kockeloeren, to crow
See cockalorum in American Heritage Dictionary 4
Origin: Perhaps alteration (influenced by Latin -ōrum, genitive pl. ending)
Origin: of obsolete Flemish kockeloeren, to crow
Origin: , of imitative origin.