As nouns the difference between boyness and coyness
is that boyness is (nonstandard) the state or condition of being a boy; masculinity, boyhood while coyness is the property of being coy.
boyness
English
Noun
(-)
(nonstandard) The state or condition of being a boy; masculinity, boyhood. coyness
English
Noun
(en-noun)
The property of being coy.