steadfast C2+

/ˈstɛdfæst/ firmly fixed in purpose or loyalty; unwavering

bedfast C2+

/ˈbɛdˌfæst/ confined to bed by illness; bedridden

fastener C2+

/ˈfæsənɚ/ a device that holds or joins things together

fastness C2+

/ˈfæstnəs/ a secure stronghold, or the quality of being firmly fixed

handfast C2+

/ˈhændˌfæst/ a betrothal or marriage sealed by clasping hands; to pledge thus