hesitation vs hesitancy

hesitation and hesitancy both are nouns.

Word	Noun	Adjective	Verb	Adverb
hesitation	Yes	No	No	No
hesitancy	Yes	No	No	No

As nouns, hesitation and hesitancy are synonyms defined as:

Other synonyms of hesitation include disinclination, indisposition, reluctance.

hesitation (noun)	hesitancy (noun)
the act of pausing uncertainly	a certain degree of unwillingness
a certain degree of unwillingness	a feeling of diffidence and indecision about doing something
indecision in speech or action