IPA: /ʌn.kəmˈpleɪ.nɪŋ.li/
KK: /ʌnˈkɒmplɪnɪŋli/
In a way that shows no complaints or dissatisfaction, accepting things as they are without expressing unhappiness.
She uncomplainingly accepted the difficult situation and continued to work hard.
Uncomplainingly → It is formed from "un-" (meaning not), "complaining" (from Latin "complainere", meaning to express dissatisfaction), and "-ly" (meaning in a manner). The word describes the manner of not expressing dissatisfaction or complaints.
Think of 'not' ('un-') expressing dissatisfaction ('complaining') — that's why uncomplainingly means doing something without complaints.