Fool wasting time on central Colombian dialect (5)
I believe the answer is:
idiom
'dialect' is the definition.
(I know that dialect can be written as idiom)
'fool wasting time on central colombian' is the wordplay.
'fool' becomes 'idiot' (synonyms).
'wasting' suggests deleting specific letters.
'time' becomes 't' (abbreviation).
'on central colombian' becomes 'm' (I can't explain this - if you can you should give a lot more credence to this answer).
'idiot' with 't' taken out is 'idio'.
'idio'+'m'='IDIOM'
Can you help me to learn more?
(Other definitions for idiom that I've seen before include "Saying specific to a certain language" , "Peculiar term" , "Phrase such as over the moon" , "Characteristic style, vocabulary" , "Word usage peculiar to a specific group" .)