Pressured - pressurised

Pressure was originally a noun. It was used from 1382 in the sense of 'the weight of emotion' etc. In the sense of 'the act of pressing' it dates from 1601, and, in a more scientific and technical sense, e.g. the idea of air pressure, from 1660.

As a verb, to pressure is not recorded before 1939. To my taste, it is an unnecessary conversion of a verb from a noun. My feeling was that there was a perfectly good verb - to pressurize - already.

However, research - as so often in the field of language - has changed my beliefs. I find, from the OED, that the verb to pressurize is, contrary to my previous belief, relatively modern. It was first used in 1944, in the sense of 'creating artificial pressure in an aeroplane'. The figurative sense - to subject to emotional (etc) pressure or persuasion - is even newer.

So I withdraw my prejudice.

If your teachers still have views about this word, you might consider the traditional British English usage - [verb + noun] construction. Instead of saying to pressurize OR to pressure, say apply pressure to ... or bring pressure to bear on.

Even more traditionally, the practice was to use the verb to press itself. «The courtiers pressed King Cnut to turn back the tide.»