When it comes to expressing the idea of treating someone harshly or severely, there are a number of synonyms for the phrase "deal hardly with". For instance, one might say that a person is being treated "ruthlessly", "cruelly", "unfairly", or "sternly". Other options include "oppressively", "brutally", "mercilessly", or "rigorously". The specific word choice may depend on the context and the severity of the treatment being described, as well as the speaker's tone and intended impact. Ultimately, however, all of these synonyms convey a sense of someone being mistreated or subjected to harsh conditions, highlighting the inherent cruelty and injustice of such treatment.