The Tweezer Pattern is a two day pattern indicating either a market high or market low. 
A Tweezer Top pattern has highs of the candlesticks equal and is a bearish reversal pattern.  These candlesticks can be of real bodies, shadows or dojis.
       
A Tweezer Bottom pattern has lows of candlesticks equal and is a bullish  reversal pattern.Candlesticks can be of real bodies or shadows or doji’s. 

Psychology of the Tweezer pattern is that both bears or bulls are not able to push the prices further up or down and hence are considered as a trend reversal. 
Tweezer Top occurs during an uptrend. On Day1 bulls push prices higher, Then, on Day2  bears  reverse the market sentiment i.e market does not breach the prior day’s highs, and heads straight down, often eliminating most of the prior period’s gains.

Tweezer Bottom  occurs during a downtrend. On Day1  bears  push prices down by pushing the price near low and then, on Day2  bulls reverse the market sentiment i.e market does not breach the prior day’s low instead  price of the security goes up, often eliminating most of the prior day’s losses for bulls.

Practice Tweezer Pattern – Beginner