push the envelope

Fig. to expand the definition, categorization, dimensions, or perimeters of something. The engineers wanted to completely redesign the product, but couldn't push the envelope because of a very restricted budget.

to move beyond the limit of what has usually been done or was the accepted standard TV shows are really pushing the envelope by showing so much sex and violence.

Exceed the limits of what is normally done, be innovative, as in They are pushing the envelope in using only new fabrics for winter clothing. This idiom comes from aviation, the envelope alluding to the technical limits of a plane's performance, which, on a graph, appear as a rising slope as limits of speed and stress are approached and falls off when the capacity is exceeded and the pilot loses control; safety lies within these limits, or envelope, and exceeding them exposes pilot and plane to risk. [Slang; late 1960s]

To exceed or try to exceed the existing limits of a discipline or activity.