This word is a slang in Sri Lanka ( Sinhala/Sinhalese ) and the meaning of this word is Lying or Lie. Basically, if someone lying to you about something then you can use this word.
Ex: 1
In English - Dont lie about it
In Sinhalese - E gana Pacha kiyanna epa
Ex:2
In English - Why are you lying?
In Sinhalese - Ai oya Pacha kiyanne?