Item Status is a condition of a weapon or item.
Prototype weapons are only available in levels 0 and 1. They can be taken after blueprint of the weapon gets created in workshop. They are usually cheap and have low statistics. After level 3, they become useless and should be replaced with weapons of higher level. Default weapons are not available in prototype status.
Broken weapons are available in any level. They have lower stats and are worse than Normal weapons. They also don't work properly and can jam while firing. When the weapon jams, you won't be able to fire for very short period of time until it gets back to normal. This can make many problems in combat. Broken weapons can still be stronger than prototypes, because they can be get in higher levels too. They can be bought in normal shop or Slot Machine after "Weapon" reward.
Normal weapons don't have flaws and work properly, but don't have any special modifications. Normal weapons do not have any special effects, and have unaltered stats. They can be purchased in normal shop or won on Slot Machine after "Weapon" reward.
Refined weapons are slightly improved versions of normal ones, with small modifications. They also have increased stats. They appear less frequently in shop and they can be won on Slot Machine after "Refined" reward.
Flawless are almost perfect weapons. Flawless weapons have the highest stats for a weapon at its level (only Custom is better than Flawless). Their appearance changes with modifications. These modifications are usually scopes, better iron sights, suppresors and laser sights. Blades don't have these modifications if they have flawless status. Flawless weapons appear in store rarely. In Slot Machine, they can be won after "Flawless" reward
Custom weapons are the "perfect" weapons, highest stats for the weapon at its level, heavily modified and usually have powerful additional effects. They are gold plated. Every weapon has it's custom version, which has a different name. They are extremely rare items in shop and Slot Machine. They can be won after "Perfect" reward.
Poop items are not weapons but garbage items won only on Slot Machine. They have the lowest selling price of all items and can't be taken to the inventory.