The question asks to select the synonym of the verb "to gnaw". To find the correct synonym, it's essential to understand the meaning of "to gnaw" and then compare it with the meanings of the given options.

Gnaw: Understanding the Verb

The verb "to gnaw" means to bite or chew on something persistently, often causing it to wear away or be consumed. This action typically involves small, continuous bites. For example, a rodent might gnaw on a piece of wood, or a persistent worry might "gnaw" at someone's mind.

Synonym Analysis: Comparing Options

Let's carefully analyze each of the provided options to determine which one is the closest synonym for "to gnaw":

• to nibble: This verb means to take small bites out of something, often in a gentle or delicate manner. For instance, someone might nibble on a piece of cheese. The core action of taking small, repeated bites is very similar to "to gnaw." While "gnaw" can imply more forceful or destructive biting, "nibble" shares the characteristic of continuous, small-scale biting. This makes "to nibble" a strong candidate for being a synonym.
• to drool: This verb refers to the act of saliva flowing from the mouth, typically unintentionally. For example, a baby might drool when teething. This action has no relation to biting or chewing; it is purely about the discharge of saliva. Therefore, "to drool" is not a synonym for "to gnaw."
• to slaver: This verb is very similar in meaning to "to drool," also referring to the act of letting saliva run from the mouth. Additionally, "to slaver" can mean to act in an excessively fawning or obsequious way. Neither of these meanings involves biting or chewing. Thus, "to slaver" is not a synonym for "to gnaw."
• to split: This verb means to divide something into two or more parts, or to break it apart. For example, you might split a log or split a decision. This action is about separation or division, not about biting or chewing persistently. Therefore, "to split" is not a synonym for "to gnaw."

Identifying the Correct Synonym

Based on the detailed analysis of each option, "to nibble" is the most fitting synonym for "to gnaw." Both verbs describe an action involving taking repeated, small bites. Although "gnaw" often suggests a more persistent or even destructive biting action, and "nibble" implies smaller, more delicate bites, they share the fundamental meaning of continuous biting.

Therefore, the correct synonym for "to gnaw" is "to nibble."