A neutral candlestick represents a period in which the bulls and bears fought hard for control over the currency pair, but neither group won. Therefore, the day is considered a neutral trading day. (A neutral candlestick will have greater impact as part of a larger candlestick trading pattern, but that is considered an advanced charting tool.)
The neutral candlestick can be either white (bullish) or black (bearish) though these terms do not hold the same impact as in the above charts. They simply mean that the closing price was either higher than the opening price as in a bullish day or the closing price was lower than the opening price as in a bearish trading day. Notice the neutral candlesticks above. A neutral candlestick will have a short body (or small body) with long shadows in both directions. For this reason, these candlesticks are called Spinning Tops.