1. What does it mean?
알빠임 turns 알 바, something one needs to care about, into a blunt rhetorical question. It can dismiss a concern, but in cheering or challenge contexts it can mean that an intimidating obstacle will not stop the speaker from trying.
Also written or said as alppaim
2. The nuance
The target matters: brushing off another person's feelings is different from brushing off predictions that your team will lose. The playful spelling does not make it automatically friendly.
3. Examples
“상대가 강하다고? 알빠임, 우리는 일단 해보자.”
The opponent is strong? So what—let's give it a try anyway.
“친구 고민에는 알빠임 같은 말 대신 이야기를 들어 줬어.”
Instead of replying dismissively to my friend's worries, I listened.
Sources
References support the meaning and usage. Example sentences are written for NoCapWiki.