v. i. [ imp. & p. p. Illapsed p. pr. & vb. n. Illapsing. ] [ L. illapsus, p. p. of illabi; pref. il- in + labi to fall, slide. ] To fall or glide; to pass; -- usually followed by into. Cheyne. [ 1913 Webster ]

n. [ L. illapsus. See Illapse, v. i. ] A gliding in; an immisson or entrance of one thing into another; also, a sudden descent or attack. Akenside. [ 1913 Webster ]

They sit silent . . . waiting for an illapse of the spirit. Jeffrey. [ 1913 Webster ]