Hi there.

You should write the name as mentioned in your Class X or Class XII Board's admit card. Those would be taken as the ID Proof. By ID proof, if you mean Aadhar Card, then that won't matter because Aadhar Card is not compulsory. 

Logically, the full name of a candidate must be written and is easily accepted but your case is peculiarly unique. The best possible advice would be to call the authorities of NTA NEET to make them aware of your situation. They are the only people who would be able to give you a concrete solution to this problem. 

Try calling the helpline numbers mentioned on the official website of NTA NEET.

Hope this helps.

Dear Chaturya, your name should be ideally as it is in tje certificates. So thats absolutely fine. If the authorities think it is an issue, they will notify the same at your registered contact no# and Email id and you can correct it during the correction window which opens in January.