Menace is usually used as both noun and adjective. Menace (as noun) = (1) something that is a source of danger: ‘These street gangs are a social menace.’ (2) a threat or the act of threatening: ‘He spoke with desperate menace.’
Menacing (as adjective) = indicating evil intent or suggesting tragic developments: ‘He was convicted of menacing behavior.’
Menace is not often used as a verb. It appears mainly in formal styles. Menace (as verb) = pose as a probable threat to; a possible danger: ‘His mighty war machine continues to menace neighboring countries.’
When you are talking about something, which is a danger to peace, survival, safety, health, happiness, etc, use threaten: ‘These poisonous liquids threaten the drinking water supply of two million people.’ ‘AIDS could threaten the economic well-being of Asian countries.’