size of it vs situation

size of it and situation both are nouns.

Word	Noun	Adjective	Verb	Adverb
size of it	Yes	No	No	No
situation	Yes	No	No	No

As nouns, situation is a hypernym of size of it; that is, situation is a word with a broader meaning than size of it:

size of it: the actual state of affairs
situation: the general state of things; the combination of circumstances at a given time

Other hypernyms of size of it include state of affairs.

size of it (noun)	situation (noun)
the actual state of affairs	a job in an organization
	physical position in relation to the surroundings
	the general state of things; the combination of circumstances at a given time
	a condition or position in which you find yourself
	a complex or critical or unusual difficulty