Correct spelling for the English word "LESTLY" is [lˈɛstli], [lˈɛstli], [l_ˈɛ_s_t_l_i] (IPA phonetic alphabet).
I apologize, but "lestly" appears to be an uncommon word and doesn't have an established dictionary entry. However, it seems to be derived from the adverb "lest," which does have a recognized definition.
"Lest" is an archaic word that is not frequently used in modern English, but can still be found in literature or older texts. It serves as a conjunction or preposition meaning "in order to prevent any possibility that something will happen" or "for fear that." Its primary purpose is to introduce a clause expressing a negative purpose or to introduce a negative outcome that should be avoided. "Lest" is often associated with cautionary or imperative language.
For example, "He double-checked his work, lest any errors remain unnoticed" means that he reviewed his task thoroughly to ensure no mistakes were left undiscovered. Here, "lest" denotes precaution and expresses the purpose of avoiding unnoticed errors.
As for "lestly," while it doesn't have an established meaning, one could assume that it is a derivative or variation of “lest.” Considering its similarity to the original term, it is possible that "lestly" could be used as an adverbial form, meaning "in a manner that prevents a negative outcome" or "with cautionary intent," although its specific usage would need to be confirmed through contextual evidence or additional information.