Where does “inky” come from?

Inky comes from Middle English -y, Middle French -ie, Latin -ia, Latin -ivus, Latin -ia, and Proto-Indo-European -kos, ultimately deriving from a Proto-Indo-European suffix.

inky (English): Of the colour of ink, especially black ink; dark;...

Definitions

Of the colour of ink, especially black ink; dark;...

Ancestry of “inky”, step by step

inky traces back through two separate lines of ancestry.

via English ink

Step	Language	Word	Meaning
1	English	ink	A pigment -based fluid used for writing, printing...
2	Middle English	ynke	ink
3	Old French	enque	ink
4	Latin	encaustum	the purple-red ink used by the later Roman...
5	Latin	encaustus	burned in, encaustic; the encaustic mode of...
6	Ancient Greek	ἔγκαυστος	burned in
7	Ancient Greek	ἐν-	in, within; on
8	Ancient Greek	ἐν	in, on, at; among; in, at, or during the time of
9	Ancient Greek	δέρμα	skin, hide
10	Ancient Greek	γλυφή	carving, carved work; hole cut
11	Ancient Greek	-ῐ́ᾱ	{{l\|en\|-ia}}; "suffix forming abstract feminine...
12	Proto-Indo-European	-íh₂	—
13	Proto-Indo-European	-h₂	Creates collective nouns, which refer to groups...

via English inquisitor

Step	Language	Word	Meaning
1	English	inquisitor	A person who inquires, especially searchingly or...
2	Old French	inquisiteur	—
3	Latin	inquisitor	searcher; inquisitor, tracker, detective, spy;...
4	Latin	inquiro	I seek after, search for, inquire into something;...
5	Latin	īn-	un-, non-, not
6	Latin	în	in, at, on, upon, from (space)
7	Latin	en	lookǃ beholdǃ; reallyǃ?; come onǃ
8	Proto-Italic	en	in

Words derived from “inky”

Every word from Proto-Indo-European -h₂ →Every word from Ancient Greek -ῐ́ᾱ →Every word from Ancient Greek ἐν- →