scrutinizer

noun
UK /ˈskruː.tɪ.naɪ.zər/
US /ˈskruː.t̬ən.aɪ.zɚ/

A person who looks at things very closely to check them.

The teacher was a careful scrutinizer of every student's homework.


OTHER MEANINGS

2. Someone who studies something in great detail to find mistakes or hidden facts.

As a scrutinizer of old documents, she noticed a tiny change in the signature.

3. A tool or program that checks data very carefully.

The software acts as a scrutinizer, scanning each file for errors.

4. A person who watches others closely and critically.

He felt nervous under the gaze of the curious scrutinizer across the room.