overt act

if it gives aid and comfort to the enemy at the immediate moment of its performance, it qualifies as an overt act within the constitutional standard of treason. The act may be unnecessary to a successful completion of the enemy's project; it may be an abortive attempt; it may in the sum total of the enemy's effort be a casual and unimportant step. But if it gives aid and comfort to the enemy at the immediate moment of its performance, it qualifies as an overt act within the constitutional standard of treason.

In criminni law. An open, manifest act from which criminality may be implied. An open act, which must be manifestly proved. 3 Inst. 12. An overt act essential to establish an attempt to commit a crime is an act done to carry out the intention, and it must be such as would naturally effect that result unless prevented by some extraneous cause. People v. Mills, 178 N. Y. 274, 70 N. E. 786, 67 L R. A. 131. In reference to the crime of treason, and the provision of the federal constitution that a person shall not be convicted thereof unless on the testimony of two witnesses to the same "overt act," the term means a step, motion, or action really taken in the execution of a treasonable purpose, as distinguished from mere words, and also from a treasonable sentiment, design, or purpose not issuing in action.

Defined under Overt in Black's Law Dictionary.

In criminal law. An open, manifest act from which criminality may be implied, An open act, which must be manifestly proved. 3 Inst. 12.