slacking his gait somewhat, the tormented young man lifted his hat in order to run his hand viciously through his hair, which he seemed to blame for everything.
"Harlequin and Columbine"
Booth Tarkington
"That you have," said Adam, slacking his horse to glance back.
"A Daughter of the Land"
Gene Stratton-Porter
Are they slacking worse than usual?
"The Law-Breakers"
Ridgwell Cullum