Under the MISCELLANEOUS OFFENCES (PUBLIC ORDER AND
NUISANCE) ACT
Intentional Harassment,
Alarm or Distress
13A. (1) Any person who in a public place or in
a private place, with intent to cause
harassment, alarm or distress to another person
(a) uses threatening, abusive or insulting words or behaviour;
or
(b) displays any writing, sign or other
visible representation which is threatening, abusive or
insulting,
thereby causing that person or any other person harassment, alarm
or distress, shall be guilty of an offence and shall be liable
on conviction to a fine not exceeding
$5,000.
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Under the PENAL CODE (CHAPTER 224)
Chapter XVII: Offences
Against Property
Extortion.
383. Whoever intentionally puts any person in fear of any injury to that person or to any
other, and thereby dishonestly induces the person so put in fear to
deliver to any person any property or valuable security, or
anything signed or sealed which may be converted into a valuable
security, commits extortion.
Punishment for extortion.
384. Whoever commits extortion shall be punished with
imprisonment for a term of not less than
2 years and not more than 7 years and with caning.
Chapter XXII: Criminal
Intimidation, Insult, Annoyance
Word or gesture intended to insult the modesty of a
woman.
509. Whoever, intending to
insult the modesty of any woman, utters any word, makes any
sound or gesture, or exhibits any
object, intending that such word or sound shall be heard, or
that such gesture or object shall be seen by such woman,
or intrudes upon the privacy of such
woman, shall be punished with imprisonment for a term which may
extend to one year, or with fine, or with both.
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Moral-of-the-story: It's amazing what the law can do. 
