The difference between Nerf and Renew

When used as verbs, nerf means to bump lightly, whether accidentally or purposefully, whereas renew means to make (something) new again.

Nerf is also noun with the meaning: the weakening or worsening of a character, a weapon, a spell, etc.

check bellow for the other definitions of Nerf and Renew

Nerf as a verb (motor racing):

To bump lightly, whether accidentally or purposefully.

Examples:

"A racer will often nerf another as a psychological tactic."

Nerf as a verb (slang, video games, especially of developers rather than players):

To cripple or weaken (a character, a weapon, a spell, etc.).

Examples:

"The lightning spell was originally pretty powerful, but in the sequel they nerfed it so it became completely useless."

Nerf as a noun (slang, video games):

The weakening or worsening of a character, a weapon, a spell, etc.

Renew as a verb (transitive):

To make (something) new again; to restore to freshness or original condition.
Renew as a verb (transitive):

To replace (something which has broken etc.); to replenish (something which has been exhausted), to keep up a required supply of.
Renew as a verb (theology):

To make new spiritually; to regenerate.
Renew as a verb (now, _, rare, intransitive):

To become new, or as new; to revive.
Renew as a verb (transitive):

To begin again; to recommence.
Renew as a verb (rare):

To repeat.
Renew as a verb (transitive, intransitive):

To extend a period of loan, especially a library book that is due to be returned.

Examples:

"I'd like to renew these three books.&emsp; nowrap Did you know that you can renew online?"