adj

• (obsolete, rare) Subject to death; mortal.
  "[…]he ſuffred hym ſelfe to be made mortall and dedly, that innocent & gyltles in hym ſelfe: he myght be ſlayne & deye for the gylty man."
• (informal) Very boring.
  "“I don't mean all of your friends—only a small proportion—which, however, connects your circle with that deadly, idle, brainless bunch—the insolent chatterers at the opera, the gorged dowagers, the worn-out, passionless men, the enervated matrons of the summer capital,[…]!”"
• (informal, Australian Aboriginal, Ireland, Newfoundland) Excellent, awesome, cool.

adv

• (obsolete) Fatally, mortally.
  "[P]erceiving himſelfe deadly wounded by a ſhot received in his body, being by his men perſwaded to come off and retire himſelfe from out the throng, anſwered, he would not now ſo neere his end, beginne to turne his face from his enemie[…]"