1. To make one feel sick or disgusted.
2. To squick over a bizarre and distasteful situation.
3. My friend Brad in a speedo. *mentally squicking right now*
Disgusting, icky, weird, often referring to something that is squelchy - imagine poking a vat of goo, and the sound you will make is similar to "squick".
Commonly known as the after-effect to "Hoomah". Squickey is the sound that your newborn creates after being launched down the stairs. The sound is a high pitched, squeaky sound that irritates your ear drums very thoroughly.