Synonyms of deadly in English:

deadly


See definition of deadly

adjective

1‘certain mixtures of drugs can be deadly’

SYNONYMS
fatal, lethal, mortal, death-dealing, life-threatening
dangerous, destructive, injurious, harmful, pernicious, detrimental, deleterious, unhealthy
noxious, toxic, poisonous
terminal, incurable, untreatable, malignant
literary deathly, nocuous, mephitic
archaic baneful
ANTONYMS

harmless, beneficial

2‘the two men rapidly became deadly enemies’

SYNONYMS
mortal, irreconcilable, implacable, remorseless, relentless, unrelenting, unappeasable, unforgiving, merciless, pitiless
bitter, hostile, antagonistic, murderous, fierce, grim, savage
informal at each other's throats

3‘I noted their deadly seriousness’

SYNONYMS
intense, great, marked, extreme, excessive, immoderate, inordinate
ANTONYMS

mild

4‘he was deadly pale and too weak to speak’

SYNONYMS
deathly, deathlike, ashen, ghostly, white, pallid, wan, pale, ghastly

5‘his aim is deadly’

SYNONYMS
unerring, unfailing, impeccable, perfect, flawless, faultless, assured, sure, true, precise, accurate, correct, exact, direct, on target, on the mark
British inch-perfect
British informal spot on, bang on
vulgar slang shit hot
ANTONYMS

poor, inaccurate

6‘life in a small village can be deadly’

SYNONYMS
boring, dull, dull as ditchwater, dreary, uninteresting, unexciting, uneventful, uninspiring, unstimulating, humdrum, lacklustre, dry, dry as dust, arid, flat, bland, monotonous, unrelieved, lacking variety, lacking variation, tedious, tiresome, tiring, wearisome, irksome, trying, frustrating, mind-numbing, soul-destroying
informal no great shakes, not up to much, nothing to write home about
British informal samey
North American informal dullsville, ornery
ANTONYMS

exciting


adverb

1‘her voice was deadly calm’

SYNONYMS
completely, absolutely, totally, utterly, perfectly, entirely, wholly, fully, quite, dead, thoroughly
in every way, in every respect, in all respects, one hundred per cent, every inch, to the hilt, to the core