1. What does it mean?
양학 shortens 양민학살, literally a massacre of ordinary people. In gaming it is a harsh metaphor for a highly skilled or overpowered player dominating beginners or lower-level opponents, rather than facing a close match.
Also written or said as yanghak
2. The nuance
The violent wording is figurative in this context. It often criticizes unfair matchmaking or deliberate beginner-stomping; winning easily alone does not prove someone manipulated their rank.
3. Examples
“실력 차가 너무 커서 경기가 양학처럼 보였어.”
The skill gap was so large that the match looked like beginner-stomping.
“초보 방에서 양학하지 말고 비슷한 실력끼리 하자.”
Let's play against similarly skilled people instead of crushing a beginners' room.
Sources
References support the meaning and usage. Example sentences are written for NoCapWiki.