Sometimes a pirate can be a pest or a player is simply overwhelmed by chat and whispers. To this end, a player can choose to Ignore another pirate.
This means that they will not receive any whispers from that character and their other chat will not display. If you ignore someone you will not be able to see their chat (plus everything the pirate said in your chat log), crew them, friend them, etc.
Also the word IGNORED will appear over their heads.
If a pirate is spamming you in whisper, blank spaces will appear in your chat box instead of what they're saying.
To Ignore, click on the pirate character or their name in the Chat or the Hearties menu. Then, under the Pirate Profile - select Take Action then Ignore. You can also choose to Unignore (restore their chat by returning to their Profile and re-selecting).
Should a pirate Report another for bad behavior, that pirate will automatically be ignored.