verb (intr, preposition)
to examine or investigate
to discover the true nature ofI can't see into your thoughts
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Investigate; see look into.
Understand the true character or nature of, as in Mother could see into Mary very well and knew exactly what she was up to. Shakespeare used this idiom in 2 Henry VI (3:1): “Well hath your Highness seen into this duke.”
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.