Strong’s Greek
G196 — akribestatos
The entry below is Strong’s own definition (1890, public domain), and every verse where the word occurs.
ἀκριβής
akribestatos — pronounced ak-ree-bes'-ta-tos
superlative of akribes (a derivative of the same as 206); most exact:--most straitest. see GREEK for 206
1 occurrence in the KJV.
Acts 26:5
Which knew me from the beginning, if they would testify, that after the most straitest sect of our religion I lived a Pharisee.