perceptiveness vs secernment

perceptiveness and secernment both are nouns.

Word	Noun	Adjective	Verb	Adverb
perceptiveness	Yes	No	No	No
secernment	Yes	No	No	No

As nouns, secernment is a hypernym of perceptiveness; that is, secernment is a word with a broader meaning than perceptiveness:

perceptiveness: delicate discrimination (especially of esthetic values)
secernment: the cognitive process whereby two or more stimuli are distinguished

Other hypernyms of perceptiveness include discrimination.

perceptiveness (noun)	secernment (noun)
the quality of insight and sympathetic understanding	the cognitive process whereby two or more stimuli are distinguished
delicate discrimination (especially of esthetic values)	the organic process of synthesizing and releasing some substance
perception of that which is obscure
a feeling of understanding