restraint - limit, moderation⏎
virtual - almost, nearly, not completely, electronic, digital, web-based⏎
rival - competitor, contender⏎
upkeep - maintenance, preservation⏎
variable - changeable, non-uniform⏎
spec - specification, detailed description⏎
rules - regulations, orders⏎
tentative - experimental, cautious, provisional, not definite,⏎
sample - tester, taste, example, small amount⏎
stringent - severe, very strict, strictly controlled⏎