Brownish means somewhat brown or having a slight brown color mixed with another shade. A brownish leaf might be turning from green to brown as autumn arrives. Brownish hair isn't quite brown but has brown tones mixed with blonde or red. Brownish water in a stream might contain mud or rust that gives it a slight brown tint.

The ending -ish turns colors into approximations rather than pure shades. Just as reddish means “sort of red” and greenish means “kind of green,” brownish describes something that's in the brown family without being fully, deeply brown. When you're trying to describe a color precisely, brownish helps you communicate that in-between quality. A brownish gray wall, a brownish yellow leaf, or brownish spots on a banana all capture colors that aren't quite one thing or another but lean toward brown.