espiar
/esˈpjaɾ/ · B1 · verb
to spy, to spy on (act as a spy)
👀🔍 e-SPI-ar has spy hidden inside it: same Germanic root as English spy
Both words come from Old French espier, which was borrowed from a Germanic verb meaning to watch. Spanish added the usual e- before s+consonant, as in escuela or España. Strip it off and spiar is just spy with the -ar verb ending.