Unreal Comparisons
To describe someone who acts a certain way but isn't really that way (like a know-it-all), we use unreal comparisons: "He behaves as if..."
Because the comparison is hypothetical or contrary to fact, you must use the subjunctive mood (Konjunktiv II) for the verb in the "as if" clause, such as wäre (were) or hätte (had).
The Word Order of "als"
To say "as if", we use the conjunction als. When als is used this way, it has a special word order rule: it triggers verb-first (V1) word order in the subordinate clause.
The conjugated Konjunktiv II verb comes immediately after als, followed by the subject. (Think of it as "...als wäre er..." instead of "...als er wäre...").
Putting on Airs
You can use this grammar structure to complain about people who are eingebildet (conceited) or hochnäsig (snooty). To describe their behavior, pair als comparisons with verbs like sich benehmen (to behave), wirken (to appear/seem), or sich aufspielen (to put on airs).
Other Konjunktiv II Verbs
While wäre and hätte are very common, you can use any Konjunktiv II verb directly after als to describe what someone pretends to know, need, or own. Watch for forms like wüsste (knew), bräuchte (needed), or gehörte (belonged).