What’s the difference between market, limit, stop, and stop-limit orders in forex?

A market order fills immediately at the best available price, accepting some risk of slippage. A limit order sets a price better than the current market and only fills at that level or better. A stop order activates once price reaches a trigger, then becomes a market order. A stop-limit combines the two: it triggers at the stop price but only fills within a defined limit, which avoids poor fills but risks no fill in fast markets.