how does one outplay a yi?

If you are both at a standoff, stand to the side of minions, wait for him to use his Q. If he does, initiate onto him immediately. You can negate a lot of burst if he does this.

Unless you absolutely needed to use your channel interrupting CC to initiate on the opponent, make sure to save any CC of that kind you have for the moment Master Yi begins to meditate. Alternatively, stop activating abilities and get ready for his Alpha Strike if you really don't have any hard CC and you think you won't be able to kill him in the middle of his Meditate (Seriously though, don't underestimate how tanky Master Yi gets when he meditates).

Anypoint after the laning phase, be absolutely sure to stand near somebody with Hard CC if you are squishy or don't have Hard CC in general.

Invest in vision denial if he split pushes a lot and prepare ambushes. Shut Yi down hard.

hes squishy with a lot of damage, he dies fast, jump on him first before he jumps on you, same thing you do as adc vs adc lategame

Thornmail, Frozen Heart/Randuins.