Rugged means rough, hard and able to take punishment. A rugged coastline is all cliff, rock and broken edge; a rugged phone case survives being dropped on concrete.
Land is rugged when it is uneven and hard to cross — rugged hills, rugged terrain — which is stronger than hilly and carries a hint of hardship. Equipment is rugged when it is built deliberately strong: rugged boots, a rugged laptop for building sites. A man's face can be rugged, and that is a compliment: weathered and strong-featured rather than smooth. Say it in two syllables with the ending sounded, RUG-gid, the way you say wicked and ragged, not "rugd".
1adjectiverugged(Of land) rough, rocky and uneven.
“The rugged path climbed straight up the hillside.”
synonyms: rocky, uneven
2adjectivesturdyStrongly built and able to survive rough treatment.
“The camera is rugged enough to take out on the boat.”
synonyms: sturdy, hard-wearing
3adjectivemans(Of a man's face) strong and weathered in an attractive way.
“He had a rugged face and three days of grey stubble.”
Rugged started out shaggy. Middle English took it from Old Norse rogg, "tuft, shagginess" — the same root that gives us rug — and it described hair before it described hillsides. Icelandic still uses rogg for shagginess, and Swedish ruggig means shaggy to this day.
Old Norse
rǫgg — tuft, shagginess
Middle English
rugged
English, today
rugged
From Middle English rugged, roggyd, ruggyd, derived from Old Norse rǫgg (“tuft, shagginess”), equivalent to rug + -ed. Compare gmq-osw ruggoter (“wrinkled”), Swedish rugga (“to roughen”), Swedish ruggig (“shaggy”), Icelandic rögg (“shagginess”), Old Norse raggaðr (“tufted”), dialectal Danish raggad (“shaggy”).
Etymology from Wiktionary, CC BY-SA