Guiart m. Old Saxon widu, wido, Old High German witu 'wood' + Old Saxon hard, Old High German hart 'strong, hard'.

Belgium

Old French

● 14thC Guiars (nom) AnNam p. 143, Gyars (nom) ibid. p. 143

Middle French

● 1351 Guiart AnNam p. 144

France

Latin

● 1135 Guiardi (gen) clairvaux-12thc 7, Guiardo (abl) ibid. 7, Guiardus (nom) ibid. 7, Wiardus (nom) ibid. 7; 1138x1162 Wiardi (gen) ibid. 73, Wiardo (abl) ibid. 62, Wiardus (nom) ibid. 61; 1145 Wiardus (nom) ibid. 11; c1147 Guiardi (gen) CartNDdOurscamp LXII; 1147 Guiardi (gen) clairvaux-12thc 14, Guiardo (abl) ibid. 14, Guiardus (nom) ibid. 14; 1147x1153 Guiardo (abl) ibid. 26; 1147x1162 Guiardi (gen) ibid. 55, Guiardo (abl) ibid. 55, Guiardus (nom) ibid. 55, Wiardus (nom) ibid. 49; 1152x1156 Guiardus (nom) ibid. 31; 1158 Wiardus (nom) ibid. 33; 1158x1170 Wiardus (nom) ibid. 138; a1163 Wiardo (abl) ibid. 98, Wiardus (nom) ibid. 96; 1163 Guiardi (gen) ibid. 99, Wiardi (gen) ibid. 95; 1163–64 Wiardi (gen) ibid. 106, Wiardo (abl) ibid. 106, Wiardus (nom) ibid. 106; 1164 Guiardus (nom) ibid. 122, Viardi (gen) ibid. 120, Wiardi (gen) ibid. 120, Wiardo (abl) ibid. 120, Wiardus (nom) ibid. 120; 1166 Wiardus (nom) ibid. 129; 1171 Guiardus (nom) ibid. 140, Wiardus (nom) ibid. 139; 1172 Wiardus (nom) ibid. 149; 1173 Wiardus (nom) ibid. 153; 1174 Wiardi (gen) ibid. 161; 1179 Guiardi (gen) ibid. 178, Guiardus (nom) ibid. 178, Viardi (gen) ibid. 176, Viardo (abl) ibid. 176, Viardus (nom) ibid. 176, Wiardi (gen) ibid. 178, Wiardo (abl) ibid. 176, Wiardum (acc) ibid. 175, Wiardus (nom) ibid. 174, Wuiardus (nom) ibid. 178; 1190 Wiardi (gen) CartNDdOurscamp CV; 1214 Wiardi (gen) ibid. CXLI; 1378 Wiardi (gen) hanquetvol1 314

Old French

● 1292 Guiart 1292paris p. 1; 1296 Guiart paris1296 p. 17; 1301 Wiart (obl) MemPic-vol17 p. 282; 1313 Guiart Paris1313 p. 12