1) STUPID PERSON (a stupid or silly person).
2) MODEL (a large model of a human, especially one used to show clothes in a shop).
3) NOT REAL (something that is not real and is used for practice or to deceive).
4) Smooth rubber or plastic object that is given to a baby to suck in order to comfort it and make it stop crying.
You will get the appropriate answer with the context.
Student or Learner