highest-pressure

Adjective

high-pressure (comparative higher-pressure, superlative highest-pressure)

1. Operating at relatively high pressure, such as several times atmospheric pressure.

   Antonyms:

   low-pressure

2. (figuratively) Tense; stressful.
   • High-pressure situations can lead to nervous breakdowns.
3. (figuratively) Involving much persuasion.
   • High-pressure salesmanship on the part of the Electro-Motive subsidiary of the General Motors Corporation, which has built by far the largest proportion of the American diesels to date, there certainly has been - to such an extent, indeed, as to compel the old-established builders of steam...1961 February, Cecil J. Allen, “Locomotive Running Past and Present”, in Trains Illustrated, page 85

See all 4 meanings of high-pressure