Cram (krm), v. t. [imp. & p. p. Crammed (krmd); p. pr. & vb. n. Cramming.] — Webster enters it under “cram”
Etymology: [AS. crammian to cram; akin to Icel. kremia to squeeze, bruise, Sw. krama to press. Cf. Cramp.]
1. To press, force, or drive, particularly in filling, or in thrustung one thing into another; to stuff; to crowd; to fill to superfluity; as, to cram anything into a basket; to cram a room with people. Their storehouses crammed with grain. Shak. He will cram his brass down our throats. Swift.
2. To fill with food to satiety; to stuff. Children would be freer from disease if they were not crammed so much as they are by fond mothers. Locke. Cram us with praise, and make us As fat as tame things. Shak.
3. To put hastily through an extensive course of memorizing or study, as in preparation for an examination; as, a pupil is crammed by his tutor.
2 other Webster entries under this spelling
Cram, v. i.
1. To eat greedly, and to satiety; to stuff. Gluttony . . . . Cr, and blasphemes his feeder. Milton.
2. To make crude preparation for a special occasion, as an examination, by a hasty and extensive course of memorizing or study. [Colloq.]
Cram, n.
1. The act of cramming.
2. Innformation hastily memorized; as. a cram from an examination. [Colloq.]
3. (Weaving)
A warp having more than two threads passing through each dent or split of the reed.
Shades of meaning
Fernald lists crammed only as an antonym, under vacant.
He lists it without comment; the entries above explain its neighbors.