The most common and most likely answer to this crossword clue is the 6 letter word INDUCT
I've seen this crossword clue in The Daily Telegraph
I
N
D
U
C
T
More clues leading to the result INDUCT
Buddy explains!
The straight part
We know that "to admit as member" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case to admit as member = induct.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 INDUCT mean?
INDUCT verb- To bring in as a member; to make a part of.
- To formally or ceremoniously install in an office, position, etc.
- To introduce into (particularly if certain knowledge or experience is required, such as ritual adulthood or cults).
- To draft into military service.
- To introduce; to bring in.