IPA: /ˌæbəˈreɪʃənl/
KK: /æbəˈreɪʃənl/
Describing something that deviates from what is normal or expected, often in a way that is unusual or irregular.
The scientist noted that the aberrational data points could skew the results of the experiment.
Aberrational → It is formed from "aberration" (from Latin "aberratio", meaning a wandering away) and the suffix "-al" (meaning pertaining to). The word "aberrational" refers to something that is pertaining to or characteristic of a deviation from the normal or typical path.
Think of 'wandering away' ('aberration') to remember that 'aberrational' means relating to a deviation from what is normal.