The word "extrinsic" is most clearly contributes to the academic style of Dan Pink's book "Drive: The Surprising Truth About What Motivates Us". This is because "extrinsic" is a technical term used in motivation psychology to refer to factors that are external to the individual and that motivate them to engage in a behavior. In contrast, "intrinsic" motivation refers to factors that are internal to the individual and that motivate them to engage in a behavior.
Extrinsic motivation is often contrasted with intrinsic motivation, which refers to the performance of an activity without any apparent reward. Extrinsic motivators are external factors such as money, praise, or promotion. Intrinsic motivators are internal factors such as the satisfaction of completing a task or the enjoyment of the activity itself.