Timorous
Etymology
From Latin timor, "fear, dread," via the medieval Latin timorosus, "fearful." The root verb timere meant "to fear," and it lies behind "timid" and "intimidate" as well. Timorous keeps that root close to the surface: it describes a temperament governed by apprehension.
adjective · /TIM-ur-us/
Nervous and easily frightened; showing or feeling a lack of courage.
What it names
The trembling caution of someone who approaches every choice braced for the worst.
Example
She gave a timorous knock at the director’s door, half hoping no one would answer.
Related idea
Timid names a settled disposition toward shyness; timorous is more vivid and active, foregrounding trembling fear in a particular moment.