cy ‧ ber ‧ stalk ‧ ing /ˈsaɪbəˌstɔːkɪŋ $ -bərˌstɒːk-/ BrE AmE noun [uncountable]
the illegal use of the Internet, email, or other electronic communication systems to follow someone or threaten them:
The state’s first cyberstalking laws went into effect a little over a year ago.
—cyberstalker noun [countable]