Contronyms/antagonym – words that can mean the opposite of themselves. My favourite sources of confusion:
- cleave – to separate into or adhere two parts
- custom – something usual or special
- dust – to add fine particles or to remove fine particles
- fast – to move fast or to stuck fast
- sanction – to approve or to boycott
- screen – to show or to hide something
- skinned – with the skin on or with the skin removed – very annoying in cookbooks
- transparent – something that is invisible or bloody obvious
- weather – to withstand the elements or to be worn down by them
Give me wisdom 
Nice list. I hadn’t ever thought about it before.
Don’t forget dust-to sprinkle a thin layer on (as a cake dusted with powdered sugar) or to remove particles from a surface (dusting the house)
fast – one cannot define a word with the use of the same word in the definition
True – ‘Fast – moving quickly or stuck in the same place’ seemed a bit opaque so I switched to using an example.