a dab hand at vs competent

a dab hand at

competent

adj
  • Resistant to deformation or flow. 

  • Having sufficient skill, knowledge, ability, or qualifications. 

  • Having jurisdiction or authority over a particular issue or question. 

  • Adequate for the purpose. 

  • Permeable to foreign DNA. 

How often have the words a dab hand at and competent occurred in a corpus of books? (source: Google Ngram Viewer )