Oppress

This is one of the 117 mis-spellings listed as 'Common difficulties' in the section on 'Spelling' within 'Writing' in UEfAP.

The verb 'to oppress' can be spelled wrongly. It is spelled accurately here - as are the forms oppresses, oppressed and oppressing.

It is mostly used nowadays to mean 'to tyrannize over', 'to hold [usually a people, ot group of people] in unjust subjection'. Until the nineteenth century, it was also used (usually in the past participle form oppressed [by] to describe the feeling of being overpowered by some emotion such as depression, sleepiness, or grief etc.

Note that the '-p-'s and '-s-'s are double -  
and that all other letters are single, although there are sometimes two '-e-'s.

The same is true of the related nouns oppression and oppressor, and the adjective oppressive.