an unpleasant, often strong, emotion caused by anticipation or awareness of danger, or a state marked by this emotion

Man's loneliness is but his fear of life — Eugene O'Neill

anxiety or solicitude

reason for alarm; danger

archaic profound reverence and awe, esp towards God

to be afraid of (somebody or something); to consider or expect (somebody or something) with alarm

Let me assert my firm belief that the only thing we have to fear is fear itself — Franklin D Roosevelt

to believe (something) with regret

I fear you are mistaken

archaic to have a reverential awe of (God)

(+ for) to be afraid or apprehensive

I fear for your safety