In the case of Ntiashagwa V Amodu (1 509) WNLR 273 the word “illiterate” has been defined to mean “a person who is unable to read and understanding and to express his thoughts by writing in the language used in the document made or prepared on his behalf.” This definition was endorsed by Kutigi JSC, later CJN (of blessed memory), in the case of His Highness V.A. Otitoju vs Governor of Ondo State & Ors (1994) SCNJ (pt.II)224 at 234.
THUMB-IMPRESSION IS PRIMA FACIE EVIDENCE OF ILLITERACY
It is trite law that mere thumb-impression on a document tantamount to prima facie as in this instant case, is prima facie evidence that the person who appended his thumb-impression is/was an illiterate. In this case, the appellant has the burden to readily prove to the satisfaction of the court that he is an illiterate.
– Sanusi, JSC. Umaru Sunday v. FRN (2018) – SC.145/2013