The number of written words cannot by itself settle the question of logical simplicity or composition.
“Zayd” as a name: simple.
“ʿAbd Allāh” as a personal name: simple despite two written words.
“ʿabd Allāh” as a descriptive possessive phrase: compound.
“Zayd is learned”: compound because subject and predicate contribute separately.
This classification concerns intended signification. It should not be confused with the grammatical classification of a word or the distinction between complete and incomplete sentences.