Wilfully, Willfully
New TestamentVine's Expository Dictionary of Biblical Words
Definition
denotes "voluntarily, willingly," Heb 10:26, (of sinning) "willfully;" in 1Pe 5:2, "willingly" (of exercising oversight over the flock of God).
"to will," used in the present participle in 2Pe 3:5, is rendered "willfully (forget)" in the RV, AV, "willingly (are ignorant of)," lit., "this escapes them (i.e., their notice) willing (i.e. of their own will)." See WILL, C, No. 1, WILLING, B, No. 1.