in the offing vs onrushing

in the offing

prep
  • Within the area of the sea known as the offing; at a considerable distance from land, but visible from shore, often in reference to an approaching ship. 

  • Soon to come; likely to happen; in the foreseeable future; projected to occur; on the horizon; in the wind. 

  • At a distance, but visible. 

onrushing

adj
  • attacking 

  • rushing or flowing forward 

How often have the words in the offing and onrushing occurred in a corpus of books? (source: Google Ngram Viewer )