Where does “inefficaciousness” come from?

inefficaciousness (English) comes from English inefficacious, from English efficacious, from Old French efficacieux, from Latin efficāx, from Latin efficiō, from Latin ex, from Latin commūnicō, from Latin commūnis — whale, sea monster; abyss.

inefficaciousness (English): Lack of efficacy

Definitions

Lack of efficacy

Ancestry of “inefficaciousness”, step by step

inefficaciousness traces back through two separate lines of ancestry.

via English inefficacious

Step	Language	Word	Meaning
1	English	inefficacious	Incapable of having the intended consequence; Not...
2	English	efficacious	Effective; possessing efficacy
3	Old French	efficacieux	—
4	Latin	efficāx	efficacious, effectual, powerful, efficient
5	Latin	efficiō	to make out or work out; effect, execute, complete, accomplish, make, form, compose
6	Latin	ex	A name of the letter "X"; out of, from
7	Latin	commūnicō	to impart, share
8	Latin	commūnis	common, commonplace, ordinary, general, universal, shared, shared alike, of both sides, belonging to two or more together
9	Old Latin	com(m)oinis	—
10	Proto-Italic	kommoinis	common
11	Proto-Indo-European	ḱom-moy-ni-	held in common
12	Proto-Indo-European	ḱóm	beside, near, by, with
13	Proto-Indo-European	ḱe	Deictic particle, here; Post-positional...
14	Middle English	kyt	—
15	Russian	кит	whale; genitive plural of ки́та
16	Old Church Slavonic	китъ	whale
17	Ancient Greek	κῆτος	whale, sea monster; abyss

via English Ness

Step	Language	Word	Meaning
1	English	Ness	An Ulster princess and the mother of Conchobar mac Nessa and Findchoem in the Ulster Cycle of Irish mythology. Daughter of Eochaid Sálbuide. Also the mother of Cormac Cond Longas by incest with Conchobar mac Nessa
2	Middle English	nesse	—
3	Old English	næs	not, not at all; not; first/third-person singular...
4	Proto-Germanic	nasją	foothill; headland; cape
5	Proto-Indo-European	néh₂s	nose

Every word from Ancient Greek κῆτος →Every word from Old Church Slavonic китъ →Every word from Russian кит →