- The Clarendon dictionary. By William Hand Browne, Samuel Stehman Haldeman. Published 1894. (noun) (n.) (noun)
Not liable to sin; faultless.
- The Winston Simplified Dictionary. By William Dodge Lewis, Edgar Arthur Singer. Published 1919. (adjective) (adj.) (adjective)
Not liable or subject to sin.
- Etymological and pronouncing dictionary of the English language. By Stormonth, James, Phelp, P. H. Published 1874. (adjective) (adj.) (adjective)
Not liable to sin.
- The american dictionary of the english language. By Daniel Lyons. Published 1899. (adjective) (adj.) (adjective)
- The american dictionary of the english language. By Daniel Lyons. Published 1899. (adjective) (adj.) (adjective)

Usage examples:

First came the mist of mythology, in which we discerned the new St. George, serene, impeccable moving through an orchard of ever- blooming cherry- trees, gracefully vanquishing dragons with a touch, and shedding fragrance and radiance around him.
- The Americanism of Washington by Henry Van Dyke
Suillius' family ties with Ovid and his influential position would have made it natural for Ovid to address him in the earlier books of the Ex Ponto or even in the Tristia; and it is clear from the opening of the poem that Suillius must have distanced himself from Ovid: Littera sera quidem, studiis exculte Suilli, huc tua peruenit, sed mihi grata tamen In the section that follows, Ovid asks for Suillius' assistance, rather strangely setting forth his own impeccable family background and moral purity; then he moves to the topic of Suillius' piety towards Germanicus, and in line 31 begins to address Germanicus with a direct request for his assistance.
- The Last Poems of Ovid by Ovid
The impeccable character of the little house had been against it.
- K by Mary Roberts Rinehart