The definition of deadly is something likely to be terminal or the cause of your demise, or something complete, something hateful, or something extremely boring. (adjective)
- Cancer that has spread so far that your doctor tells you that you'll live only a few more weeks is an example of something that would be described as deadly.
- If you are completely serious about something and will not change your mind at all, this is an example of when you are deadly serious.
- If you give your worst enemy a hateful glare, this is an example of when your glare can be described as deadly.
- If a class goes on for hours and hours and the teacher is droning on about something you don't care about, this is an example of when the class is deadly.
Deadly is defined as something resembling or related to death, or is something that is true to an extreme extent. (adverb)
- A vampire who is never able to see the light is an example of someone who stalk his prey while standing deadly still.
- If you are completely serious about something and will not change your mind at all, this is an example of a time when you are deadly serious.