No definitions found for 'dead certainty'
Perhaps one of these:
dutch rush,
dedecorate,
dutch harbor,
death's-herb,
death chair,
dowitcher,
dutes auriga,
dyadic arithmetic,
death grip,
dodgery,
data service unit,
dead ground,
ditch reed,
dedecoration,
death square,
death grapple,
ditcher,
diatessaron,
dutch iris,
dodger,
datagram,
dedecorous