Enclose worker carrying new flag (7)
I believe the answer is:
pennant
'flag' is the definition.
(I know that pennant is a type of flag)
'enclose worker carrying new' is the wordplay.
'enclose' becomes 'pen' (I've seen this in another clue).
'worker' becomes 'ant' (worker is a type of ant).
'carrying' means one lot of letters go next to another (in a down clue, the bottom letters carry others).
'new' becomes 'n' (common abbreviation eg NT for New Testament).
'ant' after 'n' is 'nant'.
'pen'+'nant'='PENNANT'
(Other definitions for pennant that I've seen before include "Tapering flag" , "Banner" , "Long narrow flag" , "Triangular flag" , "Standard" .)