An adjective used to describe one who...
1.) gets joy from taking advantage of other people,
2.) is aggressively sleazy, and/or
3.) is actively manipulative
Pip cracked a snively grin after outsourcing all of his labor force to children in overseas sweatshops
Mostly used when refering to a someone of small size that can't get enough of a sexual act by the same sex.
Oh Snively you little slut, you want another inch?