Brainish

And, in this brainish apprehension, kills / The unseen good old man.

Source: wiktionary

I had slain a man, Even thy sone, Amphidamas, whom, unwittingly of life I reft In a brainish moment, foolishly, when we quarrelled o'er the dice;

Source: wiktionary

Solicitude for the interests of true womanhood has put the knights errant into such a state of "brainish apprehension," that they hasten to imagine all kinds of terrible catastrophes which could not possibly happen .

Source: wiktionary

For the third, because the worke might in truth be iudged brainish, if nothing but amorous humor were handled therein, I haue inter-wouen matters historicall, which unexplaned, might defraud the mind of much content, as for example, in Queene Margarites Epistle to William de-la-Poole.

Source: wiktionary