Illapse
Illapse , intransitive verb
[Latin illapsus, past participle of illabi; pref. il- in + labi to fall, slide.]
To fall or glide; to pass; -- usually followed by into. — Cheyne
Illapse , noun
[Latin illapsus. See Illapse, v. i.]
A gliding in; an immission or entrance of one thing into another; also, a sudden descent or attack. — Akenside
They sit silent... waiting for an illapse of the spirit.