Limit (6)
'limit' is the definition.
(I know that curb is a more specific form of cumber)
This is the entire clue.
(Other definitions for curb that I've seen before include "Bit - restraint" , "Muzzle" , "'Temper, hold in restraint (4)'" , "Check or restrain" , "Strap used to restrain horse" .)
'limit' is the definition.
(I know that limit can be written as restrict)
This is all the clue.
(Other definitions for restrict that I've seen before include "Limit or regulate" , "Limit, inhibit" , "hamper" , "Circumscribe" , "Deprive of freedom" .)
'limit' is the definition.
(synonyms)
This is the entire clue.
(Other definitions for confine that I've seen before include "Keep within limits" , "Restrict (to an area)" , "pen" , "Incarcerate" , "Imprison" .)
'limit' is the definition.
(I know that cap is a more specific form of limit)
This is the entire clue.
(Other definitions for cap that I've seen before include "cover" , "Outdo; brimless hat" , "'If the . . . fits, wear it' (3" , "One on head; excel" , "Soft hat; crown" .)
'limit' is the definition.
(thesaurus)
This is the entire clue.
(Other definitions for margin that I've seen before include "Bland space around text" , "bank" , "Space at edge of page" , "Edge, border, fringe" , "Edge or space for error" .)