an adverb is a type of word that modifies or gives more information about a verb, an adjective, or another adverb. In this case, 'frantically' is an adverb that is used to describe or indicate the manner in which the subject of the sentence is performing an action with great urgency and haste.
1. The toddler frantically kicked his legs as the doctor tried to take his temperature.
2. Sue has been frantically studying for her exams every day.
3. Simon began to type frantically as the deadline approached.
when using 'frantically' as an adverb, it should be followed by a verb. In addition, the overall context should be of a state of haste or urgency. A common mistake to avoid is using 'frantically' as a noun.