What differs a coder and a hacker?

Answer 1

hacker exploits
coder builds
both can be used for good or bad

Answer 2

Coder = someone who writes code for fun in one or many programming languages
Hacker = someone who has some skills in networking, network security. He can exploit network systems for many reasons using software, programming languages, scripting language. There are different kind of hackers. The most trending hacker is black hat for malicious intention and white hat hacker whose are ethical hacker.