Hi, In this context 'Stub' is a regular verb.(It is regularly used in conjunction with the noun 'toe) He stubbed his toe. He is stubbing his toe. He will stub his toe. To 'stub' means to hit something off something else. Yesterday I stubbed my toe off the leg of a chair.

"To stub your toe" is when you are walking, and you accidentally hit your toe on something. It's really painful!