unfathomed

Youth is not less averse from change; but that is from exaggeration of its consequences, for all seems to the young so important, and so fatal. They are timid, because they know not what they fear; hopeful, because they know not what they expect. Despite their gayety of confidence, they yet dread the first plunge into life's unfathomed deep.

Man does vvith dangerous Curioſity / Theſe unfathom'd VVonders try: / VVith fancy'd Rules and Arbitrary Lavvs / Matter and Motion he reſtrains, / And ſtudy'd Lines and fictious Circles dravvs; […]