[it's high time] {informal sentence} It is overdue. * /It is […]

Bed is the poor man's opera.

[itching palm] {n.}, {slang} A wish for money; greed. * /He […]

[item] See: [COLLECTOR'S ITEM], [CONSUMER ITEMS].

[itself] See: [END IN ITSELF].

[ITYM] "I Think You Mean"; usually prefacing a humorous "correction"

[ivories] {n.} 1. Teeth. 2. The keys of a piano. 3. […]

[Ivy League] {n.} A small group of the older and more […]

[IWIAMUAFTP] "I wonder if anyone makes up acronyms for this page"

[IYDMMA] "If you don't mind me asking"