Semantically the majority of compounds are motivated units: their meaning is derived from the combined lexical meanings of their components. The semantic centre of the compound is the lexical meaning of the second component modified and restricted by the meaning of the first,
e.g.: a handbag = a bag carried in the hand;
an ear-ring = a ring to wear in the ear.
But the meaning of a compound is not a simple sum of lexical meanings of its components: the new meaning dominates over the individual meanings
of the components. The lexical meanings of both components are closely fused together to create a new semantic unit,
e.g.: a time-bomb = a bomb designed to explode at a certain time.
The meaning of the compound is also derived from the meaning of its distributional pattern.
A simple change in the order of stems with the same lexical meanings results in a drastic change in the lexical meaning of the compound,
e.g.: fruit-market is different from market-fruit;
boat-life is different from life-boat.
So, the lexical meaning of a compound is derived from the combined lexical meanings of its components and the structural meaning of its distributional pattern.
According to different degrees of motivation compounds are:
completely motivated - both components are used in their direct meanings: shoe-maker, sportsman;
partially motivated - one component - in the direct, the other - in indirect meaning: flower-bed, castle-builder;
completely nonmotivated (with lack of motivation) - there is no connection between the meaning of the compound and the lexical meanings of the components: fiddlesticks (nonsense), eye-wash (smth. said or done to deceive a person).