insecure

An insecure person feels uncertain or anxious about their place in the world.

When we talk about someone being insecure, it usually means they worry that others will judge them negatively or think poorly of them. This might happen at school when you're worried what your classmates will say about you behind your back, or on a job interview where you fear not impressing the employer enough. It's normal to feel this way sometimes, but if someone is always feeling insecure, it can hold them back from trying new things and being confident in themselves.