unskillfulness

Slight fault, unskillfulness, or negligence, either as to the sufficiency of the carriage, or to the driving of it, may render the owner responsible in damages for injury to passengers.

From The Government Class Book Designed for the Instruction of Youth in the Principles of Constitutional Government and the Rights and Duties of Citizens. by Andrew W. Young

I presume this is the first time that it has been put in print, but I fear the copy has several corruptions, occasioned by the unskillfulness of the copyist.

From Letters of a Traveller Notes of Things Seen in Europe and America by William Cullen Bryant

Mithridates concealed the loss, giving it out that it was a small defeat, nothing near so great as reported, and occasioned by the unskillfulness of the leaders.

From Plutarch: Lives of the noble Grecians and Romans by Arthur Hugh Clough

Those generals whom the nation has paid without service rendered for so many years, have, in the day of need, with some honorable exceptions, but served to injure her by their bad example or unskillfulness.

From General Scott by Marcus Joseph Wright

Thou knowest my unskillfulness; teach me the wondrous things out of Thy law and heal me.

From The World's Greatest Books — Volume 09 — Lives and Letters by Arthur Mee