Where does “необычайно” come from?

необычайно (Russian) comes from Russian необыча́йный, from Russian не-, from Russian не, from Proto-Slavic ne, from Proto-Balto-Slavic nē, from Proto-Indo-European né — not; no.

необычайно (Russian): exceptionally, extraordinarily, rarely,...

Definitions

exceptionally, extraordinarily, rarely,...

Ancestry of “необычайно”, step by step

Step	Language	Word	Meaning
1	Russian	необыча́йный	extraordinary, exceptional, unusual
2	Russian	не-	un-, non-, in-, im-, ir-, dis-, mis-
3	Russian	не	not, no, -n't, without; Idiomatic negative usage;...
4	Proto-Slavic	ne	not
5	Proto-Balto-Slavic	nē	not
6	Proto-Indo-European	né	not; no

Every word from Proto-Indo-European né →Every word from Russian не- →Every word from Proto-Balto-Slavic nē →