Old worker has nice order (7)
I believe the answer is:
ancient
'old' is the definition.
(similar in meaning)
'worker has nice order' is the wordplay.
'worker' becomes 'ant' (worker is a type of ant).
'has' indicates putting letters inside.
'order' is an anagram indicator.
'nice' anagrammed gives 'ncie'.
'ant' enclosing 'ncie' is 'ANCIENT'.
(Other definitions for ancient that I've seen before include "showing signs of wear?" , "Very old, belonging to times long ago" , "Extremely old" , "over the hill" , "Very old or belonging to times past" .)