(intransitive) To advance or increase with stealth, unnoticed (literally or figuratively).

(politics, military, idiomatic) Gradual unplanned expansion of the objectives, scope, and/or cost of a project, especially a military mission.

(informal, transitive) To make uncomfortable or afraid; to give someone the creeps.

(US, slang) A brothel or other disreputable or low-class place, especially where patrons are robbed. / (US, slang) A gambling game which moves to a different location every night.

The tendency of a design project or product cycle to accumulate more and more features or details, rather than to be completed and released at a more basic level.

(taxation) The move towards increased taxation when an inflation adjustment to a wage or salary pushes a taxpayer into a higher tax bracket (or, in a progressive taxation regime, further into a bracket).

(project management) Uncontrolled growth in the scope or requirements of a project.

The inexorable tendency for the commercial aspects of Christmas to appear earlier every year.

A small but significant tendency for spring to start earlier and for autumn to end later; the result of global warming.

(collectible games, video games, role-playing games) The gradual unbalancing of a game due to successive releases of new content, leaving the older ones underpowered.