I . a.
1.
Certain, confident, positive, as~d, fully convinced.
2.
Safe, secure, stable, firm, steady, trustworthy.
3.
Infallible, unfailing, never-failing, strong, permanent, enduring, abiding, fast, indisputable, certain.
4.
Certain, unerring.
II . ad.
Certainly, without doubt, ~ly, doubtless.