n.

1. 离开正道，脱离常轨；过失，犯规
2. 【医】精神错乱；心理失常
3. 【物】（透镜）像差；色差
4. 【生】畸变；变型

n.

1. an unwelcome deviation from what is normal.
   ▸informal a temporary mental lapse.
   ▸Biology  a characteristic that deviates from the normal type.
2. Optics  the failure of rays to converge at one focus because of a defect in a lens or mirror.
3. Astronomy  the apparent displacement of a celestial object from its true position, caused by the relative motion of the observer and the object.