To firmly maintain one's viewpoint, principles, or situation; to refuse to change one's practices or plans.
To toil; to drudge; especially, to study laboriously and patiently.
To walk or move slowly and heavily or laboriously (+ on, through, over).
To trudge over or through.
A slow or labored walk or other motion or activity.
the police, police officers
a police officer, especially a low-ranking one.