Imsuster is a combination of the words Impostor and Sus which when put together makes Imsuster so when saying "when the impostor is sus" you could instead say "When the imsuster".
1.Being indefinitely better than anybody else
2.Having improved opon something spectacularly to the point of having to be ridiculous about it
Ha punk i got MW3 now imsgooder than you.
Guess what fool i spent three days playin Black ops 2 you cant touch me no mo cause imsgooder fool. WHAT NOW PUNK! WHAT NOW!