A man is liable to acquire in his first week of Army life-together with his uniform, rifle and equipment-a nickname

A man is liable to acquire in his first week of Army life-together with his uniform, rifle and equipment-a nickname. Anyone who saw Private Quelch, lanky, stooping, frowning through horn-rimmed spectacles, understood why he was known as the Professor.
(a) What nickname had been given to Private Quelch?
(b) Why was he given that nickname?
© What does the word ‘frowning’ here mean?

(a) The nickname ‘Professor’ had been given to Private Quelch.
(b) He was given that nickname because he was a lanky, stooping person frowning through horn-rimmed spectacles, just like a professor.
© 'It means furrowing the brow to show concentration.