The term 'sound bullish' can be broken down into two crossword solutions: BELLOW (6 letters) and Sound (5 letters). BELLOW is a verb meaning to make a loud, deep sound, usually associated with an animal such as a bull. Sound is an adjective meaning to be in good condition or to appear to be true or valid. Together, the two words form the phrase 'sound bullish, ' which is used to describe a situation that appears to be optimistic or positive.