To refuse to understand things.
cast pearls before swine
To give things of value to those who will not understand or appreciate …
rocket scientist
One qualified to handle or understand things which are very complex or …
slow study
One who takes a long time to learn or understand things; a slow learne …
quick on the uptake
Able to readily understand things; aware and intelligent.
know one's own mind
To clearly understand one's own feelings, intentions, preferences, etc …