Meaning of Over Bought
This usually follows Over Sold and means a lot of traders/investors have bought the coin/token. It do occur most time after a major price breakout and traders/investors want to cash out their gains, they crash the price and new investors move in.
Thus, it usually lead to price spike as the new investors/traders pushes price up to gain profit. Over Bought trend of a coin/token could easily be identified using Indicators like RSI.