Someone who looks so lovable, adorable, etc It would be used in the context like " 아우우우우 >_< 이 사랑둥이!! " Call your friends this, then he/she will throw up, Call your lover this, then he/she will blush. People around you will get some goose bump of hatred.. I assume Cf. 귀염둥이 = someone with lots of cuteness