-y is added to nouns in order to form adjectives that describe something or someone as having the characteristics of what the noun refers to. ⇒ ...a smoky pub. ⇒ ...juicy red berries. ⇒ The process results in a much fruitier wine.
-y is added to colours in order to form adjectives that describe something as being roughly that colour or having some of that colour in it. ⇒ ...a rich, reddy, brown wood. ⇒ Her eyes were a bluey-green colour.
-y is added to a name or a noun in order to give it a more affectionate or familiar form. ⇒ 'How are you, Mikey?'. ⇒ Move the little doggy.