IPA: /sʌbˈnɔːrməli/
KK: /sʌbˈnɔrməli/
In a way that is below the normal level or standard.
The patient was performing subnormally on the tests compared to his peers.
Subnormally → It is formed from "sub-" (meaning under or below) and "normal" (from Latin "norma", meaning a standard or rule) and the suffix "-ly" (meaning in a manner). The word "subnormally" means in a manner that is below the standard or normal level.
Think of 'sub-' meaning 'under' and 'normal' referring to a standard — so 'subnormally' describes something that is below the normal standard.