"Under-estimating" Natural Recordings by Native Speakers
To underestimate someone or something means to think they are less capable, weaker, or less powerful than they actually are, often leading to overconfidence or inadequate preparation in dealing with them.
Under-aged refers to someone who is not yet of legal age, typically a child or a minor, who is not allowed to engage in certain activities, such as drinking, smoking, voting, or working in certain industries, due to their age.