trailer vs straggler

trailer and straggler both are nouns.

Word	Noun	Adjective	Verb	Adverb
trailer	Yes	No	No	No
straggler	Yes	No	No	No

As nouns, straggler is a hyponym of trailer; that is, straggler is a word with a more specific, narrower meaning than trailer:

trailer: someone who takes more time than necessary; someone who lags behind
straggler: someone who strays or falls behind

trailer (noun)	straggler (noun)
a wheeled vehicle that can be pulled by a car or truck and is equipped for occupancy	someone who strays or falls behind
a large transport conveyance designed to be pulled by a truck or tractor
an advertisement consisting of short scenes from a motion picture that will appear in the near future
someone who takes more time than necessary; someone who lags behind