Leak

Used as a verb to describe a situation where a particular bond is slowing losing value. Most often used to describe a corporate bond's spread slowly increasing.

Example: Comcast bonds have been leaking out all week. (Translation: Comcast bonds are slowly increasing in yield spread vs. Treasuries.)

One would generally interpret a leak in a particular bond as meaning there are more investors interested in selling the name as opposed to buying it. So on any given day either dealer desks or end accounts need to be enticed to buy with just a little more yield spread. The opposite would be gapping.