There are several synonyms for the term "partial excuse" which essentially means something that only partially excuses or justifies an action or behaviour. One alternative term is "mitigating factor", which refers to a circumstance that reduces the severity or culpability of an action. Another synonym could be "ameliorating circumstance", which implies that a situation or condition has been improved in some way, despite not fully excusing the action. "Extenuating circumstances" is a term frequently used in legal contexts, which refers to factors that make a behaviour or action less culpable, although they do not remove all guilt or responsibility. Lastly, "excuse rationale" can also be used to refer to a justification that only partially excuses an action or behaviour.