arrival vs attainment

arrival and attainment both are nouns.

Word	Noun	Adjective	Verb	Adverb
arrival	Yes	No	No	No
attainment	Yes	No	No	No

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

Other hyponyms of arrival include advent, coming.

arrival (noun)	attainment (noun)
accomplishment of an objective	the act of achieving an aim
the act of arriving at a certain place	arrival at a new stage
someone who arrives (or has arrived)	an ability that has been acquired by training