fingerspelling

Short definition from Wiktionary

Noun

1. 1
   The practice of representing the letters of an alphabet using just the hands to spell out words.
2. 2
   Any system for representing the letters of an alphabet using just the hands; a manual alphabet that is a representation of a written alphabet.
3. 3
   A representation of the spelling of a word using such a system.

Verb

1. 1
   present participle and gerund of fingerspell