The most common and most likely answer to this crossword clue is the 6 letter word ERASES
E
R
A
S
E
S
Buddy explains!

The straight part
We know that "blots out" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case blots out = erases.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does ERASES mean?
ERASES noun- The operation of deleting data.
- To remove markings or information
- To obliterate information from (a storage medium), such as to clear or (with magnetic storage) to demagnetize.
- To obliterate (information) from a storage medium, such as to clear or to overwrite.
- To remove a runner from the bases via a double play or pick off play
- To be erased (have markings removed, have information removed or be cleared of information).
- To disregard (a group, an orientation, etc.); to prevent from having an active role in society.
- To kill; assassinate.