' jack was obliged to limit one ' is the wordplay.
' jack ' becomes ' j ' (playing card abbreviation) .
' was obliged ' becomes ' had ' (to have to do something is to be obliged to do it) .
' to limit ' indicates putting letters inside.
' one ' becomes ' I ' (Roman numeral) .
' j '+' had '=' jhad '
' jhad ' placed around ' i ' is ' JIHAD '.
(Other definitions for jihad that I've seen before include "blessed war" , "Holy war as declared by osama Bin Laden" , "Muslim war against unbelievers" , "crusade" , "Holy war in defence of Islamic faith" .)
I've seen this clue in The Telegraph. Want a hint initially instead of a full solution? Install my app
