impending vs in the offing

impending

adj
  • Approaching; drawing near; about to happen or expected to happen. 

noun
  • Something that impends or threatens; an expected event. 

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. 

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