Artificial intelligent assistant

nailfast

nailfast, a. Obs. rare.
  [f. nail n. + fast a. Cf. MDu. nagelvast, MLG. naelvast, G. nagelfest, ON. nagl(a)fastr (Sw. nagelfast, Dan. naglefast).]
  Fastened with nails.

1428 Will W. Ward (Somerset Ho.), Ita quod nichil dict. rotefast vel naylefast inde capiat. 1640 Will Cowper ibid., All goods nailfast in the said house.

Oxford English Dictionary

yu7NTAkq2jTfdvEzudIdQgChiKuccveC e9f2105d8c77c42dc152344b20f1cdcb