What is an adjective for not many?

Here are some adjectives for "not many," depending on the nuance you want to convey:

General:

* Few

* Scanty

* Sparse

* Limited

* Insufficient

* Meagre

More specific:

* Small (for numbers)

* Rare (for occurrences)

* Infrequent (for occurrences)

* Insufficient (for quantity)

* Shortage (for quantity)

Figurative:

* Handful

* Dwindling

* Scattered

The best choice will depend on the context of your sentence.