suspicion vs suspiciousness

suspicion and suspiciousness both are nouns.

Word	Noun	Adjective	Verb	Adverb
suspicion	Yes	No	No	No
suspiciousness	Yes	No	No	No

As nouns, suspicion and suspiciousness are synonyms defined as:

suspicion (noun)	suspiciousness (noun)
being of a suspicious nature	being of a suspicious nature
doubt about someone's honesty
an impression that something might be the case
the state of being suspected