Starchly

adv. [f. STARCH a. + -LY².] In a stiff, formal or precise manner.

1704.  Swift, Let. Tisdall, 20 April, Wks. 1841, II. 439/2. In answer to all this, I might with good pretence enough talk starchly, and affect ignorance of what you would be at.

1755.  Johnson, Starchly, stiffly, precisely.