I wish it were not so! Here's the breakdown:
1.5M headwords × ~2KB average per entry >= 3GB
Each entry contains:
40 associations in the core graph
Multiple senses (up to 8) × 17 associations each = up to 136 more
Stems and morphological variants
In-game clue definitions
Longer definition entries with several types of related word lists.
The only good news is it works offline.