Unequal, a.
Etymology: [Cf. Inequal.]
1. Not equal; not matched; not of the same size, length, breadth, quantity, strength, talents, acquirements, age, station, or the like; as, the fingers are of unequal length; peers and commoners are unequal in rank.
2. Ill balanced or matched; disproportioned; hence, not equitable; partial; unjust; unfair. Against unequal arms to fight in pain. Milton. Jerome, a very unequal relator of the opinion of his adversaries. John Worthington. To punish me for what you make me do Seems much unequal. Shak.
3. Not uniform; not equable; irregular; uneven; as, unequal pulsations; an unequal poem.
4. Not adequate or sufficient; inferior; as, the man was unequal to the emergency; the timber was unequal to the sudden strain.
2 more senses
5. (Bot.)
Not having the two sides or the parts symmetrical.
Shades of meaning
Fernald lists unequal only as an antonym, under adequate.
He lists it without comment; the entries above explain its neighbors.