A crab managed with one tongue (6)
I believe the answer is:
arabic
'tongue' is the definition.
(Arabic is an example)
'a crab managed with one' is the wordplay.
'managed with' indicates an anagram.
'one' becomes 'i' (Roman numeral).
'crab' anagrammed with 'i' makes 'rabic'.
'a'+'rabic'='ARABIC'
(Other definitions for arabic that I've seen before include "Tongue" , "Language (of numbers)" , "There's a CIA bar on this language, oddly" , "Like numerals one, two, three etc." , "connected with gum" .)