hesitate (v) – to hold back, to be unwilling, to pause before doing something (because of uncertainty)
hesitation (n) – a certain degree of unwillingness, a pause due to uncertainty, doubt
hesitant (adj) – to be [someone] with hesitation, doubtful (before taking action)
1. The speaker hesitated for a while before he continued his speech.
2. I was hesitant when I first did the job. I felt like I couldn’t do it.
3. If you trust me, do everything I say without hesitation.
4. Please don’t hesitate to ask a question if you have one.