biggest

As an adjective biggest

is (big).

As a letter x is

the twenty-fourth letter of the.

As a symbol x is

voiceless velar fricative.

As adjectives the difference between amazing and biggest

is that amazing is causing wonder and amazement; possessing uniquely wonderful qualities while biggest is (big).

As a verb amazing

is .

As adjectives the difference between biggest and older

is that biggest is (big) while older is (old), elder, senior.

As adjectives the difference between biggest and concerning

is that biggest is (big) while concerning is causing concern; worrisome.

As a preposition concerning is

regarding, respecting.

As a verb concerning is

.

As a noun concerning is

that which one is concerned in; one's business.

As adjectives the difference between enormous and biggest

is that enormous is (obsolete)  deviating from the norm; unusual, extraordinary while biggest is (big).

As adjectives the difference between biggest and undefined

is that biggest is (big) while undefined is lacking a definition or value.

As adjectives the difference between biggest and immense

is that biggest is (big) while immense is huge, gigantic, very large.

As an adjective biggest

is (big).

As a noun most is

bridge (construction or natural feature that spans a divide).