What is the adjective for evasive?

There isn't a single perfect adjective that directly translates to "evasive" in the same way that "happy" is the adjective for "happiness". However, depending on the context, several adjectives can capture the essence of being evasive:

General:

* Elusive (hard to find or catch)

* Shifty (tending to change quickly or unexpectedly, especially in a suspicious way)

* Deceptive (giving a misleading impression)

* Dodging (avoiding something by moving quickly out of the way)

* Ambiguous (open to more than one interpretation)

* Indirect (not directly related to the matter at hand)

More specific:

* Taciturn (unwilling to speak)

* Noncommittal (not expressing a clear opinion or decision)

* Calculating (carefully considering the effects of one's actions)

* Furtive (attempting to avoid notice or attention)

* Wary (feeling or showing caution about possible dangers or problems)

The best choice will depend on the specific situation and the nuance you want to convey.