extravagant

As a noun taxonomy

is the science or the technique used to make a classification.

As an adjective extravagant is

exceeding the bounds of something; roving; hence, foreign.

As adjectives the difference between extravagant and extravagent

is that extravagant is exceeding the bounds of something; roving; hence, foreign while extravagent is .

Extravagant is a synonym of immoderate.

As adjectives the difference between immoderate and extravagant

is that immoderate is excessive or lacking, not consistent while extravagant is exceeding the bounds of something; roving; hence, foreign.

As adjectives the difference between decadent and extravagant

is that decadent is characterized by moral or cultural decline while extravagant is exceeding the bounds of something; roving; hence, foreign.

As a noun decadent

is a person affected by moral decay.

As adjectives the difference between extravagant and nimious

is that extravagant is exceeding the bounds of something; roving; hence, foreign while nimious is (obsolete) excessive; extravagant; inordinate.

As adjectives the difference between extravagant and imeldific

is that extravagant is exceeding the bounds of something; roving; hence, foreign while imeldific is ostentatiously extravagant, sometimes to the point of vulgarity.