sign language

deaf-mute language, communication via hand movements

A sign language (also signed language) is a language which uses manual communication, body language and lip patterns instead of sound to convey meaning—simultaneously combining hand shapes, orientation and movement of the  hands, arms or body, and facial expressions to express fluidly a speaker's thoughts. Sign languages commonly develop in deaf communities, which can include interpreters and friends and families of deaf people as well as people who are deaf or hard of hearing themselves.
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Noun
1. language expressed by visible hand gestures
(synonym) signing
(hypernym) language, linguistic communication
(hyponym) finger spelling, fingerspelling
(part-meronym) sign

Adjective
1. used of the language of the deaf
(synonym) gestural, sign(a), signed, sign-language(a)
(similar) communicative, communicatory