From Traderpedia

The hanging man is a candle formation that will usually appear at the top of an uptrend. Just as with the Hammer, it should have a shaven head (no upper or perhaps a very small shadow) and a tail (lower shadow, at least two to three times the length of the real body). Again, the real body of the hanging man can be clear or solid, but it is usually thought better if it is solid, indicating more negative pressure.

A hanging man candle at the top of an uptrend can signify that the prior trend may be broken and a reversal may be on the cards. However it is always better to wait for the next candle to form to confirm this.