When it comes to finding alternatives for the uncommon term "unrelaxable", a few synonyms come to mind. Firstly, the term "ineluctable" conveys the notion of being impossible to escape or avoid, often associated with a sense of unrelenting pressure or tension. Another option is "incessant", which depicts something that continues without pause or interruption, leaving no chance for relaxation. Additionally, "inexorable" reflects a quality that cannot be swayed or influenced, conveying a similar sense of being unyielding and resistant to relaxation. Lastly, "unyielding" captures the idea of a situation or condition that does not allow for relaxation or ease.