The old chaps meeting one Arab (6)
I believe the answer is:
yemeni
'arab' is the definition.
(I know that Yemeni is a type of arab)
'the old chaps meeting one' is the wordplay.
'the old' becomes 'ye' (resembles a historical spelling of 'the').
'chaps' becomes 'men' (chap means a man).
'meeting' means one lot of letters go next to another.
'one' becomes 'i' (Roman numeral).
'ye'+'men'+'i'='YEMENI'
(Other definitions for yemeni that I've seen before include "Relating to a republic on the Arabian Peninsula" , "language" , "Native of, eg, Aden" , "ME citizen" , "from an Arab country" .)