The most common and most likely answer to this crossword clue is the 6 letter word EUNUCH
I've seen this crossword clue in The Guardian
E
U
N
U
C
H
More clues leading to the result EUNUCH
- Brussels chief enlists a French guard for sultan
- Dot removed from untouched rendition of Greer’s female
- He had a member removed from the UN
- Falsetto‘s first number in French in Brussels church
- Virtually untouched: cut to balls for ineffective man
- Europe protecting one local church person without power
- Retired copper in birthday suit, wanting date, gets hot for palace worker
- Greek character in European Union church is one no longer tackled
- An ineffectual person's upset tone breaks the Greek character with Charlie
- Political group gets letter against church attendant
Buddy explains!

The straight part
We know that "ineffective man" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case ineffective man = eunuch.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 EUNUCH mean?
EUNUCH noun- A castrated human male.
- Such a man employed as harem guard or in certain (mainly Eastern) monarchies (e.g. late Roman and Chinese Empires) as court or state officials.
- (in translations of ancient texts) A man who is not inclined to marry and procreate.