stricten

verb

1. (ambitransitive, rare)To make or become strict; tighten

   “The Bank of Japan strictened, since August, its guidance on the fund position of city banks; it raised, as from September, the official interest rate by #0.001 (per 100 yen per diem); and it also enforced a measure for restricting the increased loans to be extended by urban banks.”

   “According to the news editors, the research concluded: “Overall, the study indicates that paraffinic HVO fuels are suitable for emission reduction with valve and injection timing adjustment and thus provide possibilities for engine manufacturers to meet the strictening emission."”

   “He has no other option than to find some laws that can be strictened, well knowing that it is wrong to make hasty legislation in a highly emotional climate.”