Is this a toxic work environment?

So I work on an admin team and when I first joined there was a new role made for coordinator of my team and my colleague was admin for 6 years so know everything about the job and even trained me and was fantastic but my boss decided to bring in her friend for the maternity coordinator role who knew absolutely nothing of the job and was starting from scratch. Then now nearly 3 years later another coordinator job came up and my boss decided to give it to my colleague who has been there for a year when I have been there 2 years and I believe she has gave the supervisor role to her because she doesn't say much or protest against her when I speak my mind and point out problems. This is the same woman who bitches openly about other co workers and signs off emails with other peoples signatures.

Is this a toxic work environment?
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