However, if you're looking for related terms, you could consider these suffixes:
* -ly: This suffix turns adjectives into adverbs, so "oppressively" would describe something that is done in an oppressive way.
* -ness: This suffix turns adjectives into nouns, so "oppressiveness" would refer to the quality of being oppressive.
There are also other words related to "oppressive" that use different suffixes, such as:
* oppression: the state of being oppressed
* oppressor: one who oppresses
* opprobrious: expressing or containing great scorn or reproach
* oppugnant: contradicting or opposing
Ultimately, the best suffix to use depends on the specific meaning you want to convey.