1. extremely good.

Their chocolate cake is just out of this world!

2. extremely expensive.

The price of gasoline is out of this world right now.

• trip up
• Trojan horse
• trot out
• trot out someone
• trot out something
• trouble with
• trouble with someone
• trouble with something
• true-blue
• true enough
• true to form
• true to type
• true to word
• true to your word
• trump card
• trust an inch
• trust someone an inch
• Truth will out.
• try for size
• try hand at
• try hand at something
• try it on
• try luck
• try on
• try on for size