With little time, language is concise (5)
I believe the answer is:
terse
'concise' is the definition.
(similar in meaning)
'with little time language' is the wordplay.
'with' means one lot of letters go next to another.
'little time' becomes 't' (abbreviation for time).
'language' becomes 'erse' (historical term for Scottish Gaelic).
't'+'erse' is 'TERSE'.
'is' is the link.
(Other definitions for terse that I've seen before include "Brusque and curt" , "Curt among trees" , "Pithy among trees" , "Crisp and brief" , "Curt, laconic of speech" .)