A mental property or a mind property is a property of a/the mind. Mental properties are studied by many sciences and parasciences. Some of these sciences are: psychology, cognitive sciences and recently also systemics.
There are three main scientific approaches to the study/modeling of mind (properties).
The basic concrete objective of all these approaches is to develop a model of mind/intelligence which could be implemented on a computer and could be considered sufficiently "human-like" to be mistaken for another human mind by a naive observer.
A simple concrete example: If someone pricks you with a pin, you will most likely feel pain. That instance of feeling pain is an instantiation of the property being in (or a) pain. It is important to distinguish between the predicate 'is a pain' which is a linguistic entity, and the property denoted by the predicate. This becomes important in the philosophy of mind when the two are confused, especially concerning intertheoretic reductionism and ontological reductionism .