Fearsome means frightening in appearance or reputation. A fearsome reputation, fearsome teeth, a fearsome opponent.
It is about the impression rather than the actual danger, which is why a fearsome reputation is the commonest use — the fear does the work before anything happens. It suits animals, weapons and opponents. Note the -some ending, which means causing or tending to: fearsome, troublesome, wholesome, all built the same way.
1adjectivefearsomeFrightening in appearance or reputation.
“The pirate captain had a fearsome scar across his face.”
synonyms: formidable, daunting
fearsome is a quality of frighteningness.
Also accepted in games: formidable
Fear plus -some, an English formation. The -some suffix means causing or tending to, as in troublesome and wholesome, and German furchtsam is built from the same parts.
Proto-Indo-European
*per- — to go through, carry forth, try
Proto-Germanic
*fērō
Old English
fǣr
Middle English
feer
English
fear
English, today
fearsome
Built from
From fear + -some. Compare German furchtsam (“fearful”, obsolete also “fearsome”); this is more closely equivalent to frightsome, however. fear comes from Middle English feer, fere, fer (“fear”), from Old English fǣr, ġefǣr (“calamity, sudden danger, peril, sudden attack, terrible sight”), from Proto-Germanic fērō, fērą (“danger”), from Proto-Indo-European per- (“to go through, carry forth, try”). Cognate with Dutch gevaar (“danger, risk, peril”), German Gefahr (“danger, hazard, risk”), Danish fare (“danger, hazard, risk”), Faroese and Icelandic fár (“accident, anger, calamity”), Norwegian Bokmål and Norwegian Nynorsk fare (“danger”), Swedish fara (“danger, risk, peril”), Latin perīculum (“danger, risk, trial”), Ancient Greek πεῖρα (“trial, experiment”), Armenian փորձ (“attempt”). a doublet of peril. The verb is from Middle English feren, from Old English fǣran (“to frighten, raven”), from the noun. Cognate with the archaic Dutch - verb varen (“to fear, to cause fear”).
Etymology from Wiktionary, CC BY-SA