Subject to inspection, or “submit offers subject to inspection”, means that the seller is not allowing the property to be viewed without an accepted offer. Some common reasons for this are privacy concerns of the occupants or uncooperative tenants.
The thought of buying a property sight unseen can be daunting for the traditional buyer, which can be used to your advantage as this will inevitably drive overall interest down.
It’s also not as bad as it seems as, under the standard purchase contract, you will have an inspection period, during which you can cancel the sale with no penalty.