List of workers on turn? (4)
I believe the answer is:
menu
'list' is the definition.
(menu is a kind of list)
'workers on turn?' is the wordplay.
'workers' becomes 'men' (man is a kind of worker).
'on' means one lot of letters go next to another.
'turn?' becomes 'u' (a 'U-turn' is a kind of turn**).
'men'+'u'='MENU'
'of' is the link.
(Other definitions for menu that I've seen before include "List of dishes on offer" , "List of options" , "Tariff" , "that can appear on computer screen" , "List of dishes available in restaurant" .)