Proto-Slavic *krěpъkъ

→ Belarusian крэпкі (inherited)

→ Bulgarian крепък (inherited)

→ Czech křepký (inherited)

→ Old Church Slavonic крѣпъкъ (inherited)

→ Polish krzepki (inherited)

→ Russian крепкий (inherited)

→ Russian крепчать (inherited)

→ Serbo-Croatian krepak (inherited)

→ Serbo-Croatian крепак (inherited)

→ Ukrainian кріпкий (inherited)

→ Old Czech křepký (inherited)