慣
カン, な.れる, な.らす

accustomed, get used to, become experienced

JLPT3 G5 S14 F1177

貫# penetrate; go through + 心 heart/emotions → condition created by going through an action/activity to the point of thorough penetration → *become/make accustomed to* → *train*; *exercise*; *custom* → *become skillful*.

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