Ultimatum word (6)
'ultimatum word' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for either that I've seen before include "Her tie (anag.)" , "Word introducing first of two 16s" , "Word introducing first alternative" , "One of two alternatives" , "offered a choice" .)
'ultimatum word' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for unless that I've seen before include "Otherwise than if" , "Conditional on" , "Except, save" , "Except on the condition that" , "Though" .)