Is spy a regular or irregular verb?

Spy is a regular verb.

A verb is regular if it follows the rules on conjugating .

Tense:

singular ---> spy --spies (change "y" to "i" and add -es) plural ---> spy -- spy (just the base form)

Present Participle:

spy --- spying (just add -ing)

Tense:

spy --- spied (change "y" to "i" and add -ed)

Past Participle:

spy --- spied (same as past tense)