Some Poskim, such as the Peri Chadash, argue that only those things which Chazal explicitly prohibited because of marit ayin are prohibited. Anything else is permitted.[7] Others, however, argue that this is not the case.[8]
Sometimes, a prohibition that seem related to marit ayin is referred to as chashad — it will cause one to be suspect.[10] Rav Moshe Feinstein (Responsa Iggerot Moshe, OC 2:40, 4:82) suggests that these are distinct categories.
He writes that marit ayin refers to cases where Chazal wanted to avoid having a person do something that might cause others to violate prohibitions, by mimicking the activity in cases that were more problematic. This is rabbinic in nature.
Chashad, on the other hand, refers to cases in which an observer may assume that the actor is violating a prohibition — and this is the biblical prohibition based on being clean in the eyes of man, which we saw above. This is true even though people should really give the “violator” the benefit of the doubt. However, as the Torah knows that this will not always happen, it forbids people from engaging in such suspicious activities. (Note that many believe that all these prohibitions are rabbinic.[11])
