1) Preventative 2) Preventive 3) Prohibitory 4) Tending to discourage 1) Preventative 2) Prohibitory 3) Steep 
• (a.) That prohibits; prohibitory; as, a tax whose effect is prohibitive.
Preventing or discouraging something, for example people are discouraged from buying a product because the price is prohibitive, i.e., too high
Pro·hib'it·ive adjective [ Confer French prohibitif .] That prohibits; prohibitory; as, a tax whose effect is prohibitive . 
[adj] - tending to discourage (especially of prices)
prohibitory adjective tending to discourage (especially of prices); `the price was prohibitive`
serving or tending to prohibit or forbid something. · sufficing to prevent the use, purchase, etc., of something: prohibitive prices.
tending to discourage, especially of prices