As a mood this can depict gloominess, dullness or even depression. But it depends what is brown in the dream so it can refer to the earth or earthiness and processes of the body. A muddy brown can suggest unclear or selfish emotions and thoughts.
Brown is in some ways black that has become more light, and so might refer to things that your bringing to awareness, or facets of yourself you have enabled to grow and express after being unconscious and unexpressed. So in some dreams brown transforms into other radiant colours, perhaps in a way a plant draws something from brown soil and transforms it into the colour of its flowers.
Excrement is brown and in some dreams the feelings show this depicting things that need to be left behind, recognised as not needed, or like manure something that is rich and needed for or holding in it the potential for growth.
Brown in regard to objects can show them as being old or worn, as leaves are that have served their purpose and are now ending their life. But brown can also relate to parts of you from the long past, or containing much experience – but also perhaps to do with feelings about ageing.
Brown animal: Your natural urges that you are probably comfortable with.
Brown clothes: Middle of the road and perhaps feelings that are a bit dull or conformist, but are easy to live with.
Brown eyes: Perhaps relates to feelings you have for someone you know with brown eyes.
Brown skin: Feelings about health and perhaps attractiveness. However, brown marks on the skin suggest either feelings about ageing, or that there is something wrong, or something has hurt your hand. See: hand.
Idioms: Brown study; browned off.
Am I experiencing or moving from feelings lacking colour, vibrancy or life?
Do I seek a comfortable situation that allows me to relax and avoid the energetic processes of life?
Does my dream relate to feelings of ageing?
Is this an old thing – and if so what do I feel it contains in terms of past experience or information?