The word postic is an adjective. It is a word that means backward but this term is no longer used in present day English.
In English its Post IT note I use to call them postic also haha
Marcel Postic has written: 'Maeterlinck et le symbolisme ..'
The part of speech for this particular word is a noun.
part of speech
The part of speech for "answer" is a noun.
adverb
what part of speech is beneath
The part of speech for "unfamiliar" is an adjective.
The part of speech of "came" is a verb.
The part of speech for "twirl" is a verb.
The part of speech for "explicit" is an adjective.
The part of speech for "indefinite" is an adjective.