The most common and most likely answer to this crossword clue is the 8 letter word EXCUSING
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More clues leading to the result EXCUSING
Buddy explains!

The straight part
We know that "Tolerating" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case tolerating = excusing.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 EXCUSING mean?
EXCUSING verb- To forgive; to pardon.
- To allow to leave, or release from any obligation.
- To provide an excuse for; to explain, with the aim of alleviating guilt or negative judgement.
- To relieve of an imputation by apology or defense; to make apology for as not seriously evil; to ask pardon or indulgence for.
- The act of making an excuse.