Abjurant Champion - Swift Abjuration

[Vincent Dragon]

Beginning at 2nd level, you can cast abjuration spells as a swift action, as if you had applied the Quicken Spell feat to them (but without any change in level). The maximum level of spell you can quicken in this way is equal to 1/2 your class level (rounded up).

1/2 of your ABJURANT CHAMPION class level or 1/2 of your TOTAL class level?

[J-H]

Abjurant Champion level... so if you are AC 4, you can quicken level 2 spells.

[erok0809]

Generally, class level refers to the level in the specific class, while character level refers to the sum of your levels. As J-H said, Swift Abjuration says "class level" and so it only cares about your level in Abjurant Champion.