IPA: /ˈlaɪ.ɪŋ.li/
KK: /ˈlaɪɪŋli/
In a way that is not truthful or honest; characterized by deception.
He spoke lyingly, trying to hide the truth from everyone.
Lyingly → It is formed from "lying" (from Old English "lygan", meaning to recline or be in a horizontal position, but also to tell an untruth) and "-ly" (a suffix meaning in a manner of). The word "lyingly" means in a manner of telling untruths or deceitfully.
Think of someone who is 'reclining' or 'not being truthful' — 'lying' refers to telling untruths, and '-ly' indicates the manner in which it is done.