IPA: /ˌʌnəˈveɪləˌbɪlɪti/
KK: /ʌnəˈveɪləˌbɪlɪti/
The condition of not being able to be accessed or used.
The unavailability of the product led to many disappointed customers.
Unavailability → It is formed from "un-" (meaning not) and "available" (from Latin "valere", meaning to be strong or to be worth). The suffix "-ity" (meaning the state or condition of) indicates the state of being not available.
Think of 'not' ('un-') being combined with 'worth' or 'strong' ('valere') to remember that 'unavailability' means the state of not being available.