loader vs longshoreman

loader and longshoreman both are nouns.

Word	Noun	Adjective	Verb	Adverb
loader	Yes	No	No	No
longshoreman	Yes	No	No	No

As nouns, loader and longshoreman are synonyms defined as:

loader and longshoreman: a laborer who loads and unloads vessels in a port

Other synonyms of loader include dock-walloper, dock worker, docker, dockhand, dockworker, lumper, stevedore.

loader (noun)	longshoreman (noun)
a laborer who loads and unloads vessels in a port	a laborer who loads and unloads vessels in a port
an attendant who loads guns for someone shooting game