threat B1

/θɹet/ declaration of an intention or a determination to inflict harm on another

threaten B2

/ˈθrɛtən/ to be a menacing indication of something:'The clouds threaten rain'

intruder B2

/ənˈtɹudɚ/ Someone who intrudes.

intrude B2

/ɪnˈtɹuːd/ thrust oneself in as if by force

intrusion B2

/ɪnˈtɹuːʒən/ The forcible inclusion or entry of an external group or individual; the act of intruding.

unobtrusive C2

/ˌʌnəbˈtɹusɪv/ not obtrusive or undesirably noticeable

protrusion C2

/pɹəˈtɹuːʒən/ The act of protruding.

protrude C2

/pɹəˈtɹud/ To cause (something) to extend above, beyond, or from a boundary or surface; to cause (something) to project or stick out.