Definition of "conditional"
A condition (a limitation or restriction).
Quotations
The former is called the law, which hath his promises, conditionals, and comminations or threats, accordingly; the other is called the gospel, or rather the free promises hanging not on conditions on our behalf, but simply on God's verity and mercy, although they require conditions, but not as hanging thereon; of which promises the gospel may well be called a publication.
1832, John Bradford, Memoirs of the Life and Martyrdom of John Bradford, page 69
GOD grant us to be clean beasts, to cleave the hoofs accordingly, that is, to give the old man meat, meet for the owers, that is, the law with his appurtenances, conditionals, promises, and comminations; and to give to the new man the gospel and sweet free promises, as appertaineth; and then doubtless we shall walk in the right high-way unto eternal life, that is, in Christ Jesus, the end of the law and the fulfilling of the promises, in whome they be yea and Amen.
1837, The Letters of the Martyrs: Collected and Published in 1564, page 363
For mine own part, I confess I do not in any measure think it needful to insist upon the conditionals of these assertions of the Holy Ghost, as to the removal of any or all the oppositions that from them, of old or of late, have been raised and framed against the doctrine of the saints' perseverance, there being in neither of the texts insisted on either name or thing inquired after, nor any one of all the severals inquired into, and constantly in the Scriptures used, in the description of the saints and believers of whom we speak.
1853, John Owen, edited by Rev. William H. Goold, The Works of John Owen, D. D., page 640