Adverbial use meaning 'in its entirety' or 'without leaving anything behind'. Often used with verbs like 取る, 食べる, 忘れる.
お金をそっくり取られてしまった。
I had all my money taken.
I ate the whole cake by myself.
exactly alike; spitting image; identical
Adjectival use (often with だ/な) meaning 'strikingly similar' or 'looking just like'. Commonly used as そっくりだ or そっくりな.
He is the spitting image of his father.
This painting is drawn exactly like the real thing.
The thief stole everything in the safe, leaving nothing behind.
He looks exactly like his father.
The twins are wearing identical-looking clothes.