Example sentence - He wished bad for his girlfriend because she ditched him. I know one word which is curse (a solemn utterance intended to invoke a supernatural power to inflict harm or punishment on someone or something) from searching Google, but it sounds too intense and can't be used in routine.
You can use wish ill upon as in
I would never wish ill upon anyone, but I hope never to see her again.
The following are informal
If the two parties are in the same place, then one of them can give the other the evil eye. A slightly cruder, less formal expression is giving someone a stink eye. The recipient of the stink eye doesn't necessarily need to know it - it can be given behind their back. If you can't actually see the other person, you'll have to settle for sending them bad vibes.
If you hope someone has bad luck, you could wish bad juju on someone.
If you have a superstition that some small action on your part could bring them bad luck, you can jinx them by performing that act. (West Coast AmE)
I just googled "curse synonym" and here's a cleaned-up version what I got:
- a solemn utterance intended to invoke a supernatural power to inflict harm or punishment on someone or something. "she'd put a curse on him" synonyms: malediction, hex, jinx;
a cause of harm or misery. synonyms: evil, blight, scourge, plague, cancer, canker, poison
an offensive word or phrase used to express anger or annoyance. "his mouth was spitting vile oaths and curses" synonyms: obscenity, swear word, expletive, oath, profanity, four-letter word, dirty word, blasphemy;
invoke or use a curse against. "it often seemed as if the family had been cursed" synonyms: put a curse on, put the evil eye on, anathematize, damn, hex, jinx; archaic: imprecate "it seemed as if the family had been cursed"
be afflicted with. synonyms: afflict, trouble, plague, bedevil "she was cursed with feelings of inadequacy"
utter offensive words in anger or annoyance. "drivers were cursing and sounding their horns" synonyms: swear, blaspheme, take the Lord's name in vain
So if you're going to wish for something bad to happen to someone, your best option is probably just going to be 'curse', Sandeep. Usually only witches or other magic practitioners can hex or jinx people, but anyone can curse someone. For example:
Damn you to Hell, you whoring harlot! May your hair always have split ends, and may everything you eat taste like feces!
I just made that up that curse. I wished for the harlot to be plagued and bedeviled with bad hair and disgusting food. She would have to hear it (or read it in a letter) to know about it, but I'm not a witch and nothing's keeping me from saying it.
The verb befall is a good one here. It takes as a subject something (typically bad) that might happen to someone. For some occurrence to befall someone means that the occurrence happened to the person.
A common usage:
He wished some horrible fate would befall her.
An additional thought:
As discussed in the comments, it's common to make explicit the particular horrible fate you would wish upon someone.
If you wish to leave it generic, the term horrible fate is reasonably common. For example:
He wished some horrible fate upon her.
Compared to the statement above with befall, this is more active.