This is an irregular feature - both in frequency and oddness - dedicated to a word I came across that I have never previously used.
indagate (IN-duh-gayt) v. to investigate; to search into; to inquire; to research.
The archaic word indagate comes from the Latin indagatus, which is the past participle of indagare ("to search"). There are also related derivatives of indagate, including the nouns "indagation" and "indagator" and the adjective "indagative."
I came across the word while wasting time in the 1828 edition of Samuel Johnson's Dictionary of the English Language. Johnson suggested that indigate can also mean "to beat out," presumably in terms of a suspect's confession.
No Guantanamo Bay jokes, please.