I think this is founded on the
Latin, I beg permission to quote the following portion of my note on Jug.
ii. 3. in my edition of Sallust:

"_Incorruptus_, [Greek: aphthartos] , _i. e._ incapable of dissolution,
the _incorruptibilis_ of the Fathers of the Church. In imitation
probably of the Greek verbal adjective in [Greek: tos], as [Greek:
hairetos], [Greek: streptos], etc., the Latins, especially Sallust,
sometimes used the past part. as equivalent to an adj. in _bilis_:
comp. xliii, 5.; lxxvi. 1.; xci. 7.; Cat. I. 4.,

{438}

'Non _exorato_ stant adamante viae;' Propert. IV. 11. 4.,
'Mare scopulis _inaccessum_;' Plin. _Nat. Hist._, XII. 14.

It is in this sense that _flexus_ is to be understood in Virg. _AEn._,
v. 500."

The same employment of the past part. is frequent in our old English
writers, and I rather think that they adopted it from the Latin. The
earliest instance which I find in my notes is from Golding, who renders the
_tonitrus et inevitabile fulmen_ of Ovid (_Met._ III. 301.):

"With dry and dreadful thunderclaps and lightning to the same,
Of deadly and _unavoided_ dint."

In Milton I have noticed the following participles used in this sense:
_unmoved_, _abhorred_, _unnumbered_, _unapproached_, _dismayed_,
_unreproved_, _unremoved_, _unsucceeded_, _preferred_. But as Milton was
addicted to Latinising, I will give some examples from Shakspeare himself:

"Now thou art come unto a feast of death
A terrible and _unavoided_ danger."--_1 Hen. VI._, Act IV. Sc. 5.

"We see the very wreck that we must suffer,
And _unavoided_ the danger now,
For suffering so the causes of our wreck."--_Rich. II._, Act II. Sc. 1.

"All _unavoided_ is the doom of destiny."--_Rich. III._, Act IV. Sc. 4.

"Inestimable stones, _unvalued_ jewels."--_Ib._, Act I. Sc. 4.

"Tell them that when my mother went with child
Of that _insatiate_ Edward."--_Ib._, Act III. Sc. 5.

"I am not glad that such a sore of time
Should seek a plaster by _contemned_ revolt."--_King John_, Act V. Sc 2.

"The murmuring surge
That on the _unnumber'd_ idle pebbles chafes."--_Lear_, Act IV. Sc. 6.

"O, _undistinguished_ space of woman's will."--_Ib._

I could give instances from Spenser and even from Pope, but shall only
observe that when we say "an _undoubted_ fact" we mean an _indubitable_
one.

THOS. KEIGHTLEY.

P.S.--I am not disposed to quarrel with