not able to understand something quickly.

I tried to explain how the new software works to my manager, but he's a little slow on the uptake.

Usage notes: also used in the form quick on the uptake - able to understand something quickly:

He was quick on the uptake and able to realize right away what was wrong.

• someone can't be bothered to do something
• someone can't hold a candle to
• someone can't hold a candle to someone else
• someone can't hold a candle to something else
• someone could do something with eyes closed
• someone could do something with eyes shut
• someone could do something with their eyes closed
• someone could do something with their eyes shut
• someone couldn't care less
• someone could with eyes closed
• someone could with eyes shut
• someone could with their eyes closed
• someone could with their eyes shut
• someone, eat your heart out!
• someone from hell
• someone gets religion
• someone has got game
• someone has more bark than bite
• someone is at disposal
• someone is at your disposal
• someone is in business
• someone of a certain age
• someone par excellence
• someone's answer
• someone's answer someone