125th vs hundred-and-twenty-fifth

125th and hundred-and-twenty-fifth both are adjectives.

Word	Noun	Adjective	Verb	Adverb
125th	No	Yes	No	No
hundred-and-twenty-fifth	No	Yes	No	No

As adjectives, 125th and hundred-and-twenty-fifth are synonyms defined as:

125th and hundred-and-twenty-fifth: the ordinal number of one hundred twenty-five in counting order

125th (adjective)	hundred-and-twenty-fifth (adjective)
the ordinal number of one hundred twenty-five in counting order	the ordinal number of one hundred twenty-five in counting order