What suffix goes with critic coward loyal sick invent trick free informal to make them a noun?

Here are the suffixes that can be added to the words you provided to make them nouns:

* -ic: critic (already a noun)

* -ard: coward (already a noun)

* -al: loyal (already a noun)

* -ness: sick becomes sickness

* -ion: invent becomes invention

* -ery: trick becomes trickery

* -dom: free becomes freedom

* -ity: informal becomes informality

Let me know if you'd like to explore more word building techniques!