short temper vs irascibility

short temper and irascibility both are nouns.

Word	Noun	Adjective	Verb	Adverb
short temper	Yes	No	No	No
irascibility	Yes	No	No	No

As nouns, short temper and irascibility are synonyms defined as:

Other synonyms of short temper include quick temper, spleen.

short temper (noun)	irascibility (noun)
a feeling of resentful anger	a feeling of resentful anger