Learn Hardcore Hindi: डेबिट कार्ड गुम है।

In डेबिट कार्ड गुम है, गुम is not the main verb in the same way lose is in English. It functions more like an adjective/state word: lost / missing.

So the structure is closer to:

Debit card is lost
The debit card is missing

The actual finite verb is है = is.

Why is the sentence डेबिट कार्ड gुम है and not something with a verb meaning to lose?

Hindi often expresses this idea as a state rather than an action.

So instead of saying:

I lost my debit card

you can say:

Debit card is lost / missing → डेबिट कार्ड गुम है।

This is a very natural way in Hindi to describe the situation when something cannot be found.

If you want to express the action more directly, Hindi could also use other constructions, but गुम है is common and idiomatic for is missing / is lost.

Why is there no word for the or a in the sentence?