adjective, guilt·i·er, guilt·i·est.
Examples from the Web for guiltily
“I guess I got a little carried away in there,” I say guiltily.
"I dare say he would, ma'am," I answered, guiltily recalling Captain Branscome's own words to me on this subject.Poison Island|Arthur Thomas Quiller-Couch (Q)
Guiltily conscious of having betrayed him, she still believed that she had done him a real service in the betrayal.The Lookout Man|B. M. Bower
Terry and Arden guiltily got into a gaudy taxi with three other girls.The Orchard Secret|Cleo Garis
British Dictionary definitions for guiltily
adjective guiltier or guiltiest
Word Origin and History for guiltily
Old English gyltig, from gylt (see guilt (n.)). Of conscience, feelings, etc., 1590s. Meaning "person who is guilty" is from 1540s. To plead not guilty is from 15c.; to plead guilty is 19c., though, as OED notes, "Guilty is technically not a plea, but a confession."