Cursing

Cursing is considered a fine art among Klingons. (1) During some kind of battle game called curse warfare (mu'qaD veS), the rule is to find the best curse. In The Klingon Dictionary, curses are divided into two sorts: words you can say to somebody (epithets: "You idiot!"), and general curses somebody says when they are angry (invectives: "Dammit!")

Epithets

Epithets are name calling, that is a word you can use to insult somebody, like "idiot" or "dumbass".

maqDar	Used in DSN
petaQ	One of the most heard curses on the TV-shows
Qovpatlh	-
taHqeq	a classic insult
toDSaH	used for someone not on the best of terms
yIntagh	this also means "life support system", but there is no known relation

Invectives

Invections are exclamations said in anger, like "damn".

baQa'	-
ghay'cha'	-
ghuy'	General invective, somewhat like "Damn!"
ghuy'cha'	This might be said after receiving an unsettling communiqué.
Hu'tegh	-
QI'yaH	quite vulgar, this is one of the strongest, most foul curses
Qu'vatlh	said in moments of extreme anger (2)
va	shortened form of Qu'vatlh (3) It is used to show "only slight anger or distemperment" (4).

There are no canon examples for this curse, but some good examples in the Klingonist community:

va, tujqu'!
Phew! What a scorcher! (Katz)

va, yorIq Do'Ha'!
Alas, poor Yorick! (Glen Proechel's Translation of Hamlet, see ➞ Homlet)

va, Do'Ha' yorIq!
Alas, poor Yorick! (The Klingon Hamlet)

toH va!
Alas! (Rhona Fenwick, chIjwI' tIQ bom Rime of the Ancient Mariner)

Invective pronoun

The word jay' can be added at the end of a phrase in order to turn it into an invective.

qaStaH nuq?	What is happening?
qaStaH nuq jay'?	What the hell is going on?	Heard in ST6

See also

• Exclamation
• Curse warfare

References

1 : Power Klingon

2 : Conversational Klingon

3 : The Klingon Dictionary, p. 178

4 : HolQeD v3n1, Mark Shoulson