APORIA was the spirit (daimona) of difficulty, perplexity, powerlessness and want of means. She was closely associated with Amekhania (Helplessness), while her opposite number was Poros (Expediency).

Aesop, Fables 534 (from Chambry 129) (trans. Gibbs) (Greek fable C6th B.C.) :
"Herakles was making his way through a narrow pass. He saw something that looked like an apple lying on the ground and he tried to smash it with his club. After having been struck by the club, the thing swelled up to twice its size. Herakles struck it again with his club, even harder than before, and the thing then expanded to such a size that it blocked Herakles's way. Heracles let go of his club and stood there, amazed. Athena saw him and said, `O Herakles, don't be so surprised! This thing that has brought about your confusion is Aporia (Difficulty) and Eris (Strife). If you just leave it alone, it stays small; but if you decide to fight it, then it swells from its small size and grows large.'"

Plutarch, Life of Themistocles 21. 1 (trans. Perrin) (Greek historian C1st to C2nd A.D.) :
"He [the Athenian statesman Themistokles] made himself hateful to the allies also, by sailing round to the islands and trying to exact money from them. When, for instance, he demanded money of the Andrians, Herodotos says he made a speech to them and got reply as follows : he said he came escorting two gods, Peitho (Persuasion) and Bia (Compulsion); and they replied that they already had two great gods, Penia (Penury) and Aporia (Powerlessness), who hindered them from giving him money." [N.B. In the actual text of Herodotus Bia is replaced by Ananke (Necessity), and Aporia by Amekhania (Helplessness).]

Sources:

• Aesop, Fables - Greek Fables C6th B.C.
• Plutarch, Lives - Greek Historian C1st-2nd A.D.