Definition of "slog"

It is as if Mr. Faulks had bled his own prose white, draining it of emotion in order to capture the endless enervating slog of war.

1996 February 11, Michael Gorra, “Tunnel Vision”, in The New York Times‎

England's experimental line-up will have realised early on that this would be a long, hard slog against the multi-talented Brazilians with great strength in their starting line-up and on the bench.

2017 November 14, Phil McNulty, “England 0 – 0 Brazil”, in BBC Sport‎

There, despite the long slog of the pandemic and all the distracting dramas at headquarters, the schools themselves have mostly kept it together.

2022 February 12, Danny Westneat, “The reason voters see past the terrible headlines with Seattle schools”, in The Seattle Times‎

The leading engine was one of the Class Y6 2-8-8-2 compound articulateds, [...] The stack noise of one of these great brutes slogging up a grade was quite unforgettable.

1961 July, J. Geoffrey Todd, “Impressions of railroading in the United States: Part Two”, in Trains Illustrated, page 419

A miraculous desert rain. We slog, dripping, into As Safi, Jordan. We drive the sodden mules through wet streets. To the town’s only landmark. To the “Museum at the Lowest Place on Earth.”

2014, Paul Salopek, Blessed. Cursed. Claimed., National Geographic (December 2014)