Float probably. Different cleats and clipless systems different amounts of float. What cleats and pedals?
Edit… from here….
Most pedals and cleats have a degree of float to allow your feet to pivot slightly as you pedal. Float is measured in degrees and is the amount by which the foot can move before releasing from the pedal. Some cleats are zero-float, or fixed, which, as you can imagine, keeps your feet ‘locked in’ to the pedal. Other cleats are in the six-degree range. Most riders prefer a little bit of float, and many bike fitters insist that this wiggle room can help keep knees healthy.
Exactly how the cleat floats is something you want to consider too. Speedplay is well known for its ice-like feel, with virtually no friction in the float. Some riders like this feeling; others do not. Most pedals have a small amount of friction built into the system, and some pedals can be adjusted for a tighter or looser feel.
If you are unsure about what float is right for you, the good news is that your pedal choice won’t lock you into one particular setting: you experiment with the settings on the pedal, and with different cleats.
Some people like a little, some people like a lot.