The term 'VAIN Bird' can be solved by the word 'PEACOCK', which is a 7 letter word. Peacocks are birds that are known for their beautiful and colorful feathers, which they often display in a fan-like shape to attract mates. They are native to India and Sri Lanka, and have been kept as pets since ancient times. The term 'VAIN' is often used to describe them because of their tendency to show off their feathers.