The plural of proper is propers.
As in "the propers must be observed".
It could be used as a verb: "The bulldozer mounds up the soil." It is more often used as the plural noun or, if you like candy bars, a proper noun.
Plural
The plural of degree is degrees
The plural of Shears is Shears
Ceilings is the plural of ceiling
The plural of the proper noun is Carolinas.
Um, proper factors ?
The plural of the proper noun Thursday is Thursdays.
The plural of the proper noun Mia is Mias.
"Ouchies" is not a proper word. "Ow" has no plural, it is an exclamation.
The plural form of the name Castillo is Castillos.A proper noun is always capitalized.
The plural for for the name Usie is Usies.
The plural of party is parties.
The plural form for the proper noun Finn is Finns.
The plural form for the proper noun Tommy is Tommys.
Crunch does not have a plural, but "crunch" is the proper conjugation of it for a plural noun.She crunches.They crunch.
The plural is the Rusches. Use the rules for forming plural nouns to make a proper noun plural.