on the surface vs outward

on the surface

prep

  • apparently, outwardly; superficially 

outward

noun

  • A ward in a detached building connected with a hospital. 

adj

  • visible, noticeable 

  • outer; located towards the outside 

  • Tending to the exterior or outside. 

adv

  • Towards the outside; away from the centre. 

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