follower
A person who supports, copies, or learns from someone else.
A follower is someone who goes along with, supports, or learns from another person. When you follow a leader in a game of Simon Says, you're a follower, copying their movements and obeying their commands. In a school group project, some students take charge while others are followers who help carry out the plan.
The word doesn't necessarily mean weakness or a lack of thought. Followers can pay attention, learn skills, and support their team. A scientist following another scientist's research methods is building on proven knowledge. An apprentice following a master craftsperson is learning a valuable trade.
But follower can sometimes suggest someone who goes along too easily without thinking for themselves.
On social media, a follower is someone who subscribes to see another person's posts and updates. Having many followers might mean you're popular or post interesting content, though online followers are different from real-world friends.
People sometimes talk about a difference between thoughtful following (learning from teachers, cooperating with teammates, respecting good leadership) and blind following (copying others without thinking, going along with bad ideas just to fit in).