IPA: /ˈlɛtʃ.ər.əs.li/
KK: /ˈlɛtʃərəsli/
In a way that shows a strong desire for sexual activity, often in an inappropriate or offensive manner.
He looked at her lecherously, making her feel uncomfortable.
Lecherously → It is formed from "lecher" (from Old French *lecher*, meaning one who indulges in sexual desire) and the adverbial suffix "-ously" (meaning in a manner of). The word "lecherously" describes behaving in a manner that shows excessive or offensive sexual desire.
Think of someone who indulges in sexual desire ('lecher') and how they might act 'in a manner of' ('-ously') that desire. This helps you remember that 'lecherously' means behaving in an excessively sexual way.