The word 'past' as a noun means the time that has already happened. It is used to talk about things that occurred before now.
We cannot change the past.
She learned from her past mistakes.
As an adjective, 'past' describes something that existed or happened before now. It helps to tell about previous things or persons.
He is a past president of the club.
We remember past events clearly.
As an adverb, ‘past’ tells us that a time is after a certain point in hours or moments.
It's ten past six now.
The meeting started past noon.
As a verb (old or rare), ‘past’ means to go by or move beyond a place or person. It is not common in modern English.
The runner past the other quickly.
She past the shop on her way home.
In grammar, ‘past’ refers to the tense that shows an action or state happened before the present time.
I learned the past tense in class.
He told a story in the past tense.
‘Past’ can describe events or problems that are finished and no longer active or important.
That problem is past now.
Let's forget past troubles.