obsession

This untutored mathematician had an obsession with numbers.

这位未接受过正式教育的数学家对数字十分痴迷。

Her fear of flying is bordering on obsession.

她怕乘飞机几乎到了不可救药的地步。

Therefore, we should think with a calm mind, with more rationality and less sensitivity, more wit and less confusion, more calmness and less fickleness, more indifference and less obsession, more generosity and less prejudice.

因此，我们应该以平和之心思考问题，多一点理性、少一点感性，多一点睿智、少一点混沌，多一点冷静、少一点浮躁，多一点淡然、少一点痴迷，多一点大度、少一点偏执。

Fitness has become an obsession with him.

他迷上了健身。