Concept:
Fluconazole belongs to the azole group of antifungal drugs.
Step 1: Fungal cell membranes contain ergosterol.
Step 2: Fluconazole inhibits synthesis of ergosterol.
Step 3: Without proper ergosterol synthesis, fungal cell membrane function is disturbed.
Step 4: This inhibits fungal growth.
Step 5: Therefore, fluconazole is an antifungal drug.
\[
\boxed{\text{Antifungal}}
\]