IPA: //ʌnˈblʌʃɪŋ//
KK: /ʌnˈblʌʃɪŋ/
Showing no shame or embarrassment; bold or shameless in behavior or attitude.
She made an unblushing confession about her mistakes without any hesitation.
Unblushing → It is formed from "un-" (meaning not) and "blushing" (from Old English "bluscan", meaning to turn red or to blush). The word "unblushing" means not turning red, or showing no shame or embarrassment.
Think of 'not' ('un-') feeling embarrassed or 'turning red' ('bluscan') — that's why unblushing means showing no shame.