Reptilian

According to the AHD Reptilian is defined as:

1. Of or relating to reptiles.

2. Resembling or characteristic of a reptile.

3. Despicable; treacherous.

The word reptilian is derived from the word reptile which originates in Latin with the words reptus and repere which mean to creep. It also came through Late Latin as the word reptile and carried into Old French as the same word and then into Middle English as reptil. 

I think it is funny how the word reptile, was actually reptile for a good while until Middle English dropped the e, and I guess today we decided it was better to keep it. I know my chosen word is Reptilian, but it's etymology is taken from the word reptile. I really enjoy hearing the word used when describing someone who is despicable. That man has reptilian behavior; you would think his mother was a dinosaur.