When it comes to describing an improvement in health, the term "less ill" can seem a bit vague. Fortunately, there are plenty of synonyms to choose from that convey varying degrees of recovery. For example, you could say someone is "recovering," "on the mend," or "feeling better." If they're still not quite at full health, you could describe them as "improving," "getting over it," or "on the road to recovery." Additionally, you might say they're "convalescing," "recuperating," or "convalescent," which implies a state of rest and recovery. All of these phrases can be used to describe a patient who is gradually improving, albeit not fully healed yet.