diminutize

verb2

1. •
   To put (a word, name) in a diminutive form.

   • […] her name is Concepcion, diminutized: Concha […] — 1904
2. •
   To make (someone or something) appear smaller (often in a figurative sense).

   • [He] was a small wizened man whose face was diminutized by a large flat-brimmed black stetson. — 1988