IPA: /ˌʌnɪkˈsɛpʃənəbl/
KK: /ʌnɪkˈsɛpʃənəbl/
Something that cannot be reasonably criticized or found fault with; it is considered perfect or acceptable without any objections.
The committee found her proposal to be unexceptionable and approved it without hesitation.
Unexceptionable → It is formed from "un-" (meaning not) and "exceptionable" (from Latin "excipere", meaning to take out or exclude, with the suffix "-able" meaning capable of being). The word means not capable of being taken out or excluded, hence, beyond reproach or faultless.
Think of 'not' ('un-') being combined with something that is 'capable of being excluded' ('exceptionable'). This helps you remember that 'unexceptionable' means something that cannot be criticized or is faultless.