Taxes are entirely lawful, with one borderline exception . Income taxes were authorized by the l6Th Amendment in I believe l9l2 ( this may explain the traditional April l5 deadline which coincides with the Titanic disaster of that year.) The exception oddly- is not widely discussed, least of all by politicians- that is- The individual states of the United States ( this is stated early in the constitution proper)- are forbidden to charge what amount to Border Taxes for commerce between say, New York and New Jersey/ However, there are tolls on all manner of bridges and tunnels which cross state lines- a de facto border tax. As far as I know this little but factual argument- and it is in the actual constitution, not amendments- ( so is on more solid ground than say Gun control versus the 2nd amendment)- has never reached the center of Washington politics- let alone the High Court! Of course it can be stated that tolls on bridges and tunnels ( which are interstate) are merely for the maintenance and upkeep of the structures, but look it over.
One possibility is the word legal.
If you want to know whether a contract is lawful and legal then you need to have it reviewed by your attorney.
Legal, Lawful
legal
A legal eagle
Statutes.
Lawful, legal, rightful....
legal
Permitted, legal, sanctioned.
legal eagle
legal
"Lawful subject" is a term used in law and legal matters that is define through a legal dictionary. Any "subject" in lawful terms, by definition, is a person who is a "case, experimentee, liegeman, recipient, testee, or victim."