suppletive

/ˈsʌplətɪv/
adjective
  1. Relating to or being a form that is used to fill a gap in a grammatical paradigm, such as 'went' as the past tense of 'go'.
    • In English, the word 'better' is a suppletive form of 'good'.
    • The verb 'to be' has many suppletive forms, like 'am', 'is', and 'were'.
    • Linguists study suppletive patterns to understand how languages change over time.
Synonyms