Where does “impredictability” come from?

impredictability (English) comes from English predictability, from English predict, from French prédire, from Italian predicare, from Spanish predicar, from Latin praedicō, from Latin dīcō, from Latin -tiō — small stone, pebble; gravel, rubble.

Ancestry of “impredictability”, step by step

Step	Language	Word	Meaning
1	English	predictability	The characteristic of being predictable
2	English	predict	To make a prediction: to forecast, foretell, or...
3	French	prédire	to predict, foretell
4	Italian	predicare	to preach
5	Spanish	predicar	to preach
6	Latin	praedicō	to proclaim, declare publicly
7	Latin	dīcō	to say, talk, speak, utter, mention
8	Latin	-tiō	tion, -ation, -ing
9	Latin	dissertātiō	(spoken) dissertation, discourse, disquisition
10	Latin	dissertus	arranged, disposed; explained
11	Latin	disserere	second-person singular future passive indicative...
12	Latin	dis-	asunder, apart, in two; reversal, removal;...
13	Latin	calceus	shoe
14	Latin	calx	limestone; chalk; the finish line
15	Ancient Greek	χάλιξ	small stone, pebble; gravel, rubble

Every word from Ancient Greek χάλιξ →Every word from Latin -tiō →Every word from Latin dis- →