The brim of a hat is the horizontal edge that sticks out around the hat and shades your face from the sun. The brim of a glass or bucket is the top edge, or rim. When a glass is full right to the very top it is said to be full to the brim.
A light is described as dim if it is not very bright. A room that is only dimly lit is also described as dim. The lights in the picture are dim. The opposite of dim is well lit or bright.
Limbs are your arms and legs. A bird's wings are called limbs, and large branches on a tree are also called limbs.
Muslim describes anything related to the religion of Islam.
A rim is the very edge of something, usually something round like a cup or a wheel. When it is the topmost edge rather than the outer edge, it is also called the brim.
Swimming is a way of moving when you are in the water, using your arms and legs to push you fowards. There are many different ways of swimming, with names like breaststroke, freestyle, butterfly and the one that most children start with - dog paddle! You can use the word swim as a noun, as in "I am going for a swim".