First of all, prefix is a part of a word that comes at the beginning of a word joins to another word and becomes one word, e.g. under-.
Under- : it forms ➤ (verb, adjective, noun)
under is a prefix means less, lower, not enough and beneath below.
Verb Examples:
undertake
underestimate
underlie
Best source:
https://youtu.be/phEwlgjVUWQ