The most common and most likely answer to this crossword clue is the 13 letter word INCORPORATING
I've seen this crossword clue in The Guardian
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Buddy explains!

The straight part
We know that "absorbing" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case absorbing = incorporating.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 INCORPORATING mean?
INCORPORATING verb- To include (something) as a part.
- To mix (something in) as an ingredient; to blend
- To admit as a member of a company
- To form into a legal company.
- To include (another clause or guarantee of the US constitution) as a part (of the Fourteenth Amendment, such that the clause binds not only the federal government but also state governments).
- To form into a body; to combine, as different ingredients, into one consistent mass.
- To unite with a material body; to give a material form to; to embody.