the.com/opponent
The reason you sharpen the knife instead of just owning one.
means A person who competes, argues, or fights against you in a contest, debate, or conflict.
from From Latin opponere, to set against — ob (against) plus ponere (to place), literally something placed in your path on purpose.
Chess senseIn chess, your opponent is also your only honest mirror.
Word cousinShares ponere with proponent, the friend across the table.
Not enemyOpponents play by rules; enemies skip them entirely.