a word used in conjunction with s&m, consensual torture, bondage, etc - so that when you say "no" or "stop" in the heat of the moment, the other person can disregard it - the safety word is the serious-i-mean-it-now time-to-stop word. usually something ridiculus like Alabama.
"Why did Jesus die on the cross? Because he forgot his safety word."
adj. Bloated and obese. Derives from the state of a tick(parasitic insect) after it has gorged itself on a host mammal's blood. Not complimentary. I've heard it in the context of Australian slang, but I'm sure it's spoken all over the place.
"Christ! All that beer you've been guzzling latley has made you fat as a tick!"