From outlie +‎ -er.

• IPA^(key): /ˈaʊtˌlaɪə(ɹ)/
• (Canada) IPA^(key): /ˈʌʊtˌlaɪɚ/

outlier (plural outliers)

1. A person or thing situated away from the main body or outside its proper place.
   • 2023 November 1, Paul Clifton, “One account for the UK railway”, in RAIL, number 995, page 47:

     Observing as an outlier from Scotland, Hynes sums up the industry problem: "The conversation we've had for this article is really about creating an environment in which better decisions can be taken, isn't it?

2. An exception.
3. (geology) A part of a formation separated from the rest of the formation by erosion.
4. (statistics) A value in a statistical sample which does not fit a pattern that describes most other data points; specifically, a value that lies 1.5 IQR beyond the upper or lower quartile.

• inlier