If my silicone has been "inhibited" what does that mean?
"Inhibition" means that your silicone has and will not cure properly. Instead of curing to a solid state it remains whole or partially liquid, despite the components being mixed in the proper ratio - in other words a goopy mess.
Inhibition can be a problem with platinum-based silicones (tin silicones are much more forgiving) and can be caused by a variety of factors - everything from the type of gloves you are wearing (latex rubber gloves cause inhibition - vinyl and nitrile gloves do not), to the type of clay you may be trying to cast (a model sculpted from clays with sulfur in them cannot be molded in platinum-based silicone). Tin-silicones will even inhibit platinum-silicones!
If you piece is only slightly inhibited (for instance it has turned solid but retains a tacky feel) it may complete curing over time, or if exposed to heat - but there are no guarantees. If your silicone won't cure at all unfortunately there is nothing to be done but to start over. If you are molding a piece, clean it off as thoroughly as possible - including wiping it down with solvents - and try again (but ONLY once you have tested to see if you can find the source of the inhibition). If you are adding a further layer of silicone to a previously cured piece, do the same - remove all the uncured silicone, and wash the piece down thoroughly with a solvent such as acetone before trying again.
Inhibition is the reason it is important to do a TEST every time you begin a new silicone project, use a new solvent or otherwise change any aspect of your process.