What is istiḥsān in the Maliki school of thought?

Linguistically, Istihsan (juristic preference) means considering something good. Technically, it is the jurist's deviation from a clear analogy with a weak effect to a subtle analogy with a strong effect, or deviating from a ruling to custom for the people's benefit, or the jurist's deviation from a general ruling to an exceptional ruling due to evidence that he deems preponderant. The definition of Istihsan as "an evidence that occurs to the jurist but which he cannot articulate" is weak. The author of Maraqi al-Su'ud summarized Istihsan by saying: "And taking that which has preponderant strength among the evidences is Istihsan, or it is specification by custom of what is general, and some intend it as consideration of public interest."