In a premeditated manner.

Devised, contrived, or planned beforehand; preconceived, premeditated.

(obsolete, transitive) To weigh or consider beforehand; to intend. / (obsolete) To deliberate beforehand.

Third-person singular simple present indicative form of prepense

simple past tense and past participle of prepense

present participle of prepense

prepense; planned beforehand

Malice aforethought.