Proto-Slavic *silьnъ

→ Bulgarian силен (inherited)

→ Czech silný (inherited)

→ Lower Sorbian sylny (inherited)

→ Macedonian силен (inherited)

→ Polish silny (inherited)

→ Romanian silnic (borrowed)

→ Russian сильный (inherited)

→ Serbo-Croatian силан (inherited)

→ Ukrainian сильний (inherited)