Is the verbal Skydiving an infinitive, participle, or gerund?

The gerund ends in - ing and functions as a noun. The infinitive is the base form of a verb with to. A participle is a verb that ends in - ing (present participle) or - ed, - d, - t, - en, - n (past participle). Participles may function as adjectives, describing or modifying nouns. Therefore i'd say it would be participle

the word is infinitive