Definition of "slogging"

Erecting-shop work was always hard and slogging, so that at the end of a 9¾ hour day there were not many who felt inclined for much more physical activity.

1944 September and October, A Former Pupil, “Some Memories of Crewe Works—I”, in Railway Magazine, page 285

The heat of the fire, the steam which arose from the dampening water, the hard slogging at the white-hot metal of the links, and the continual pulling of lengths of chain, were calculated to put a test on the strongest of men, and often on hot summer days they had to be sent home, for the work became unbearable.

1945 January and February, A Former Pupil, “Some Memories of Crewe Works—III”, in Railway Magazine, page 14

Washed-up jerry cans and bits of lumber wriggled at the water's edge, amid the sewage and the sloggings of occasional fishermen and the spreading wake of a Vietnamese patrol boat.

1983, National Lampoon‎, volume 2, numbers 54-65