This is "to wish", as in "I wish I could" jIn.

tlhIngan jIH 'e' vIjIn
I wish I were a Klingon.

LL: In German, the verb wish can have an indirect object, which sounds awkward in English [...]

MO: No, that's something you want: Like in English, you either say "I wish I had a beer" or "just I want a beer". The verb jIn cannot have a thing as an object.

LL: What about the song "We wish you a merry Christmas..."?

MO: That's a different wish; that's not this one. It's more the -jaj solution. jIn usually has a phrase as an object, not a thing.