It is the hundred-constable which originated the term constable, and the parish constable acquired it by comparison; where the term headborough or chief pledge is used in contrast to a constable, the term constable is likely to refer specifically to the role of a hundred-constable.
The hundred-constable initiated the use of the term constable, and the parish constable adopted it through comparison; when "headborough" or "chief pledge" is used in opposition to a constable, "constable" typically refers specifically to the role of a hundred-constable.