dockworker vs longshoreman

dockworker and longshoreman both are nouns.

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

As nouns, dockworker and longshoreman are synonyms defined as:

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

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

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