diff --git a/pwgen_fr/word_db.py b/pwgen_fr/word_db.py
new file mode 100644
index 0000000..e46dbff
--- /dev/null
+++ b/pwgen_fr/word_db.py
@@ -0,0 +1,132 @@
+""" A pre-processed database of words, independant of their source """
+
+import typing as t
+from enum import Enum
+import json
+
+
+class Genre(Enum):
+    MASC = "masculin"
+    FEM = "féminin"
+
+
+class Nombre(Enum):
+    SING = "singulier"
+    PLUR = "pluriel"
+
+
+class Temps(Enum):
+    PRESENT = "present"
+    FUTUR = "futur"
+    IMPARFAIT = "imparfait"
+
+
+class Nom(t.NamedTuple):
+    """Nom commun"""
+
+    genre: Genre
+    sing: str
+    plur: str
+
+    def __str__(self) -> str:
+        return f"{self.sing}"
+
+    def accord(self, nombre: Nombre) -> str:
+        """Accorde en nombre"""
+        return getattr(self, nombre.name.lower())
+
+
+class Adjectif(t.NamedTuple):
+    masc_sing: str
+    masc_plur: str
+    fem_sing: str
+    fem_plur: str
+
+    def __str__(self) -> str:
+        return f"{self.masc_sing}/{self.fem_sing}"
+
+    def accord(self, genre: Genre, nombre: Nombre) -> str:
+        """Accorde en genre et en nombre"""
+        return getattr(self, f"{genre.name.lower()}_{nombre.name.lower()}")
+
+
+class Verbe(t.NamedTuple):
+    present_sing: str
+    present_plur: str
+    futur_sing: str
+    futur_plur: str
+    imparfait_sing: str
+    imparfait_plur: str
+
+    def __str__(self) -> str:
+        return f"{self.present_sing}"
+
+    def accord(self, temps: Temps, nombre: Nombre) -> str:
+        """Accorde en temps et en nombre (seule la 3è pers. est utilisée)"""
+        return getattr(self, f"{temps.name.lower()}_{nombre.name.lower()}")
+
+
+class Adverbe(t.NamedTuple):
+    """Packed as named tuple for consistence"""
+
+    adv: str
+
+    def __str__(self) -> str:
+        return self.adv
+
+    def accord(self) -> str:
+        """for consistence"""
+        return self.adv
+
+
+class WordDb:
+    """Base de donnée de mots, sérialisable"""
+
+    _serialize_data: dict[str, t.Type[t.NamedTuple]] = {
+        "noms": Nom,
+        "adjectifs": Adjectif,
+        "verbes": Verbe,
+        "adverbes": Adverbe,
+    }
+
+    noms: list[Nom]
+    adjectifs: list[Adjectif]
+    verbes: list[Verbe]
+    adverbes: list[Adverbe]
+
+    def __init__(
+        self,
+        noms: t.Optional[list[Nom]] = None,
+        adjectifs: t.Optional[list[Adjectif]] = None,
+        verbes: t.Optional[list[Verbe]] = None,
+        adverbes: t.Optional[list[Adverbe]] = None,
+    ):
+        self.noms = noms or []
+        self.adjectifs = adjectifs or []
+        self.verbes = verbes or []
+        self.adverbes = adverbes or []
+
+    def serialize(self) -> dict:
+        """Serialize to plain dictionary (no classes)"""
+        return {
+            attr: [x._asdict() for x in getattr(self, attr)]
+            for attr in self.__class__._serialize_data
+        }
+
+    def save(self, fd):
+        """Serialize to this stream"""
+        json.dump(self.serialize(), fd)
+
+    @classmethod
+    @t.no_type_check  # serialization is messy
+    def unserialize(cls, data: dict) -> "WordDb":
+        """Reverses :serialize:"""
+        parsed = {}
+        for attr, attr_cls in cls._serialize_data.items():
+            parsed[attr] = list(map(attr_cls, data[attr]))
+        return cls(**parsed)
+
+    @classmethod
+    def load(cls, fd) -> "WordDb":
+        """Unserialize from this stream"""
+        return cls.unserialize(json.load(fd))