42nd vs forty-second

42nd and forty-second both are adjectives.

Word	Noun	Adjective	Verb	Adverb
42nd	No	Yes	No	No
forty-second	No	Yes	No	No

As adjectives, 42nd and forty-second are synonyms defined as:

42nd and forty-second: the ordinal number of forty-two in counting order

42nd (adjective)	forty-second (adjective)
the ordinal number of forty-two in counting order	the ordinal number of forty-two in counting order