Why is ouster the act of ousting and not one who ousts?

Oyster is spelled as After English to Urdu translation of Oyster, If you have issues in pronunciation than you can hear the audio of it in the online

oust·er ouster pronunciation: aU st r part of speech: · noun · definition: the act of ousting or condition of being ousted; ejection or expulsion synonyms

ouster studio Pronunciation Dictionary

ouster pronunciation oyster - translation to Irish Gaelic and Irish Gaelic audio pronunciation of translations: See more in New English-Irish Dictionary from Foras na Gaeilge