Is ailness a synonym for sickness?

No, "ailness" is not a synonym for "sickness". While "ailness" is a somewhat archaic word that can refer to a state of being unwell, it's not as common or widely understood as "sickness".

Here's why:

* "Ailness" is a noun that often refers to a general sense of ill health or a specific ailment, but it's not used to describe the state of being sick.

* "Sickness" is a more common and versatile word, encompassing a wide range of illnesses, diseases, and conditions.

Here are some examples of how to use "ailness" and "sickness":

* "Ailness": "He suffered from a lingering ailness that weakened him."

* "Sickness": "The doctor diagnosed the patient with a serious sickness."

Therefore, while "ailness" is related to sickness, it's not a direct synonym.