Definition of underhandedly in US English:

underhandedly

adverb

  • See underhanded

    • ‘I wasn't actually trying to underhandedly insult him, as he seemed to believe; or rather I suspect he just did it for the attention.’
    • ‘But as I said earlier, all this is done, perhaps underhandedly, whilst I'm supposed to be busy working.’
    • ‘All the while doing it so underhandedly that they now believe I am completely innocent.’

Pronunciation

underhandedly

/ˌəndərˈhandədlē//ˌəndərˈhændədli/