Attendants - we dart about in ship (8)
'attendants' is the definition.
(steward is a kind of attendant)
'we dart about in ship' is the wordplay.
'about' indicates an anagram.
'in' is an insertion indicator.
'ship' becomes 'ss'.
'wedart' with letters rearranged gives 'teward'.
'teward' inserted inside 'ss' is 'STEWARDS'.
(Other definitions for stewards that I've seen before include "Racing authorities", "They look after passengers on aircraft or ship", "They look after passengers on aircraft and ships", "Crew members", "waiters".)