CFDs are a leverage product and can involve a significant risk of loss. Trading CFDs may not be suitable for all, therefore you should ensure that you understand the risks involved and take into account your individual circumstances.
Trader's Glossary

What is Slippage?

Slippage is the pip-difference between the price a trader expects an order to be filled at, and the price it is actually filled at. Slippage tends to occur when liquidity is low, or in volatile markets, particularly in the run-up to, or in the wake of, important economic data releases. Slippage also affects stop orders as these are executed as market orders which are automatically filled at the next best price rather than re-quoting another price to the trader.