What term describes someone who is absolutely essential to a team or organization?

The term "indispensable" refers to someone who is absolutely essential to a team or organization, highlighting their critical importance. This word stems from the root "dispense," which means to distribute or deal out. The prefix "in-" negates the meaning, indicating that this person cannot be dispensed with; their presence is necessary for the proper functioning of the team or organization.

In a working context, an indispensable individual often possesses unique skills, knowledge, or qualities that contribute significantly to the group's success. Their absence would create a noticeable gap that could hinder progress or productivity, illustrating the high value placed on their role.

The other choices, while they contain terms related to value and contribution, do not reflect the same level of necessity as "indispensable." "Dispensable" and "replaceable" imply that a person can be easily substituted, while "extraordinary" denotes high quality or achievement but does not specifically convey the essential nature of the person’s role within a team.