longshoreman vs dockworker

longshoreman and dockworker both are nouns.

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

As nouns, longshoreman and dockworker are synonyms defined as:

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

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

longshoreman (noun)	dockworker (noun)
a laborer who loads and unloads vessels in a port	a laborer who loads and unloads vessels in a port