A verb is a word that indicates a physical or mental action or a state of being.
Typically, a sentence has at least a subject (the actor) and a verb (the action). The verb tells us what the subject of the sentence is doing. The entire action is known as the sentence's predicate, which could be just the verb on its own or a main verb with a helping verb or could include the verb, the object (the entity or thing acted upon) and possibly an adjunct (something that adds information about the action but is not required for understanding). The predicate can include every word in the sentence but for the subject.
Here's an example:
In that sentence, CFO is the subject and the rest of the sentence is the predicate because it serves to describe what the CFO did. The CFO (subject) reported (verb) would be a complete sentence, but adding mergers and acquisitions (the object) tells us what was reported and adding for the first quarter (adjunct) gives us more information.
See a video about predicates and verbs: