There is no direct equivalent in Classical Greek for someone who is "disabled" in the modern sense, but there is a term, ἀδύνατος adunatos "without power." This is an adjective with a broad range of meanings, most commonly "unable (to do a thing)." As an adverb ἀδυνάτως, it typically means "done without skill, done ineptly, with feebleness."

There is however a subcategory of meaning, τοὺς ἀδυνάτους tous adunatous (accusative plural, "the powerless, the weak.)" Ps.Aristotle in Athenaion Politeia (Constitution of the Athenians) mentions (49.4) that the Athenian boule (council) is responsible for assessing "the powerless," who are, we learn, eligible to receive free food from the Athenian state equivalent to 2 obols per day. In this category are those with "maimed bodies" (τὸ σῶμα πεπηρωμένους) and those who possess less than three minae of wealth (and therefore are ineligible to serve as soldiers in any capacity, either as hoplites or rowers or whatever). So, at least in the Athenian system of the late 5th century, those who had received debilitating injuries in battle were in the same category with those who had received physical disabilities at birth, and they were taken care of at a minimal level by the state. There was even an official steward (tamias) to look after them. Some argue that the Greek here is meant to be understood as referring to persons who are both at once: very poor AND also physically incapacitated. I don't feel strongly about either interpretation. The Greek is fairly ambiguous.

In Lysias Funeral Oration (2.73), the same categorization is applied to those who live into advanced old age and become adunatos in body (ἐν δὲ τῷ γήρᾳ ἀδυνάτους μὲν εἶναι τῷ σώματι). Thucydides (7.28) uses the word to describe the plight of the Athenians after their many setbacks in the war, with the specific qualifier of their material prosperity: ("[the Athenians] became helpless in regards to materiel, ἀδύνατοι ἐγένοντο τοῖς χρήμασιν). We also see the term applied to ships which cannot sail properly (Herodotus 6.16).

There is another term in the Greek world, πήρωσις (perosis). The general meaning is "lameness" or "deformity." Its application is very broad, from physical deformity to even baldness (which the Greeks considered a handicap just like a birth defect). Plutarch explains that the Spartan king Agesilaus had a perosis of the leg (Age. 2.3). Those with a perosis are sometimes, but not always, among the adunatoi, depending on whether the condition prevented them from participation in the city's affairs (fighting, voting, sacrificing, dancing, etc). The Spartans, of course, are a special case when it comes to physical inability to participate. Participation for a full Spartiate was centered on battle; there was no place for disability, and not surprisingly there is basically no discussion of it among them whatsoever. It was completely anathema to them and defied categorization. That King Agesilaus had a perosis was remarkable, exceptional, extraordinary. There was also an elusive undercurrent of "get over it" at Sparta and to some degree in other Greek city-states, where those with certain disabilities were expected to compensate and "get the job done."

In the case of Philip II, debilitating injuries were of course not really equivalent to those of a common soldier in the phalanx. As a ruler, he enjoyed special privilege, and his identity was not necessarily tied up in his physical ability (although physical appearance and ability did play a big role in Macedonian society). Greek society carried with it a certain value judgment against those who carried physical disability. Look no further than the myth of Hephaestus, the lame god, who was the object of constant ridicule. Ares screws his wife and when Hephaestus catches them in the act in an elaborate contraption of snares, and calls the other gods to come see, they all just laugh, both at the situation and at poor Hephaestus. Being "whole" and even being attractive was central to Greek aesthetic. The Athenian elite called themselves the kaloi kagathoi, "the beautiful and the good."

There is actually a fairly robust body of scholarship on disability in antiquity, with a quite recent (2017) survey of the topic including topics covering the Near East, Persia, Egypt, India, China, Greece, Rome, and Late Antiquity. I was not able to look at it for this reply but it seems pretty damned cool! It is:

Christian Laes, ed. Disability in Antiquity (Routledge: 2017)

See also:

Laes, Goodley, and Rose, ed. Disabilities in Roman antiquity : disparate bodies, a capite ad calcem (Leiden: Brill, 2013).

Helen King, Health in Antiquity (Routledge 2005), especially chapter 10, " 'Curing' Disability" by Nicholas Vlahogiannis