Where does “подсматривать” come from?

подсматривать (Russian) comes from Russian подсмотре́ть, from Russian под-, from Proto-Slavic podъ- — under-.

подсматривать (Russian): to peep, to spy, to pry

Definitions

Step	Language	Word	Meaning
1	Russian	подсмотре́ть	—
2	Russian	под-	upwards; closer; adding
3	Proto-Slavic	podъ-	under-

подсматривать — Etymology, Origin & Word History | Etymology Explorer