Sentence:  The <WSD>geas</WSD> is the last effective enchantment we shall consider. A <WSD>geas</WSD> is a restriction or compulsion laid upon a person by a druid or a bard. To break a <WSD>geas</WSD> is to forfeit one's share of luck and possibly one's life....<WSD>Geasa</WSD> are not curses, but recognitions of individual needs given to protect and help an individual succeed at life. 
Meaning of the word marked with <WSD> tags:  A vow or obligation placed upon a person.