IPA: /ɪnˈdɛfɪnətli/
KK: /ɪnˈdɛfɪnɪtli/
For an unknown or unspecified period of time, without a clear end.
The meeting has been postponed indefinitely due to unforeseen circumstances.
Indefinitely → It is formed from "in-" (meaning not) and "definitus" (from Latin, meaning defined or limited) and the suffix "-ly" (meaning in a manner). The word "indefinitely" means in a manner that is not defined or limited, suggesting an endless or uncertain duration.
Think of 'not defined' ('in-') and 'limited' ('definitus') to remember that 'indefinitely' means something that is not limited in time.