The state of a security or other asset that cannot easily be sold or exchanged for cash without a substantial loss in value. Illiquid assets also cannot be sold quickly because of a lack of ready and willing investors or speculators to purchase the asset. The lack of ready buyers also leads to larger discrepancies between the asking price and the bidding price than would be found in an orderly market with daily trading activity.
Taobiz explains Illiquid
Some examples of inherently illiquid assets include houses, cars, antiques, private company interests and some types of debt instruments. On the other end of the spectrum, most listed securities traded at major exchanges, such as stocks, funds, bonds and commodities are very liquid, and can be sold instantaneously during regular market hours at fair market price.
Illiquid securities carry higher risks than liquid ones; this becomes especially true during times of market turmoil when the ratio of buyers to sellers may be thrown out of balance. During these times, holders of illiquid securities may find themselves unable to unload them at all, or unable to do so without losing a lot of money.