i Register
In some senses, inwardly is marked as obsolete. Watch for register when choosing this word.
adv
In an inward manner; to or toward the inside or to oneself.
Jacob groaned inwardly when he was called on to answer the question.
Completely, fully.
whanne Percyual vnderstode that she was his veray syster / he was inwardly glad and sayd / faire syster I shalle entre therin / For yf I be a mys creature or an vntrue knyghte there shalle I perysshe