Is it possible for someone to fake your ip address as their own, using their own device?

Question

ip address question

Answer 1

Or if you use dynamic IP address (but it's can not be called "faking", of course, You can be using one IP with someone else if you are behind a NAT). Or by spoofing if that "someone" has access to you local network (and there are no routers to control it)...

Answer 2

Only if your device can be used by hacker as proxy server (which can be a result of virus attack or errors in configuration for example).