Occur

Synonyms: Happen; exist

Synonyms: Dawn on; Strike

Verb

Odour

Synonyms: Smell; Stink

Noun

Omen

Synonyms: sign; signal

Noun

Opaque

Synonyms: Cloudy; Murky

Antonyms: Transparent; clear

Adjective

Oppress

Synonyms: persecute; abuse

Antonyms: Comfort; aid; support

verb

Optimistic

Synonyms: Confident; hopeful

Antonym: pessimistic

Ordeal

Synonyms: hardship; trial

Noun

Patience

Synonyms: Calmness; camposure

Antonym: impatience

Noun

Percive

Synonyms: notice; see

verb

Perilous

Synonyms: Dangerous; risky

Antonym: safe

Adjective

Perish

Synonyms: Die; expire

Synonyms: rot; disintegrate

Verb

Pioneer

Synonyms: Founder; Innovator

Synonyms: Establish; invent

Noun

Verb