Daunt (v): to make fearful, to intimidate

The steepness of the mountain daunted the team of amateur climbers, because they hadn’t realized what they were in for.

Dauntless: to be fearless or unintimidated

Dearth (n) lack, scarcity

There is no dearth of comedy at a convention of clowns.

Debacle (n) violent breakdown; sudden overthrow, overwhelming defeat.

A political debate would become a debacle if the candidates began screaming and throwing dinner rolls at each other.

Debauchery (n): wild living, excessive intemperance

Debauchery can be expensive; fortunately for Jeff

Debauch: to seduce or corrupt

Debilitate (v): to weaken, to cripple

The football player’s  career was ended by a debilitating injury to his knee.

Decadent (adj): decaying or decayed, especially in terms of morals.

A person who engages in decadent behavior is a person whose morals have decayed or fallen into ruin.

Decimate(v) to kill or destroy a large part of

To decimate in army is to come close to wiping it out.

Decorous(adj) proper; in good taste, orderly

Decorous behavior is good, polite, orderly behavior.

Deduce (v) to conclude from the evidence; to infer

To deduce something is to conclude it without being told it directly.

Defame (v): to libel or slander; to ruin the good name of

To defame someone is to make accusations that harm the person’s reputation.