Correct spelling for the English word "Lethy" is [lˈɛθi], [lˈɛθi], [l_ˈɛ_θ_i] (IPA phonetic alphabet).
"Lethy" does not appear to be a widely recognized or commonly used word in the English language. Consequently, it does not have a dictionary definition. It is possible that you have misspelled the word or that it is a word specific to a certain dialect or jargon. If you are referring to the word "lethy," it is also unrecognized in the English language and has no dictionary definition.
Alternatively, it is possible that you may be referring to a proper noun or a term associated with a specific field, person, or community. In such cases, the word "lethy" would not have a standard dictionary definition but could represent something unique to that particular context. Therefore, it is recommended to provide additional information or clarification on the term "lethy" to offer a more accurate and appropriate definition.