Learn German: Wir nennen diese Bewegung die perfekte Verteidigung. - We call this movement the perfect defense.

This is because the verb nennen (to call or to name) is one of the few German verbs that takes a double accusative. It needs two objects: the thing you are naming (diese Bewegung) and the name you are giving it (die perfekte Verteidigung). Both must be in the accusative case.

Is there a trick to remember the gender for Bewegung and Verteidigung?

Yes! Both nouns end in the suffix -ung. In German, almost every single noun ending in -ung is feminine. That is why they use the feminine words diese and die.

Why is the adjective ending -e in die perfekte Verteidigung?

Since Verteidigung is feminine and in the accusative case, we have to look at the article before it. Because it follows the definite article die, the adjective takes the standard weak ending -e, making it perfekte.

Could I use nennen to say 'We call the police'?

No, nennen is only used for 'calling' in the sense of giving a name or title to someone or something. If you want to talk about calling someone on the phone or calling for help, you would use anrufen (to call on the phone) or rufen (to call for or shout).