Simple-defective adjective

A simple-defective adjective is a defective adjective that is defective because it lacks a simple adjective form and only has gradative (comparative and superlative) forms.

There are a two of these in English. Both pertain to the content of lists: We can use the comparatives former and latter to refer to the contents of a list of 2 items; a list of three or more items needs the equivalent superlatives first and last. Latter/last is regular adjective, whereas former/first is an irregular adjective (we don’t say *"formest").

These may also be nominalised as to nominalised adjectives; "the former", "the latter", "the first", "the last".

Former also has a slightly different meaning akin to “previous,” so e.g. if someone talks about can talk about a former occupant, they mean “a previous occupant.” First is also an ordinal number.

It’s worth noting that many native speakers get confused by this obscure bit of grammar and mistakenly believe latter to refer to the final entry in any list regardless of length, resulting in errors such as *“A, B, and C, the latter of which…" (should be "the last of which…"), even though they are naturally familiar with the word "last" which is far much more common than "latter".