The most common and most likely answer to this crossword clue is the 5 letter word CURSE
I've seen this crossword clue in Independent
C
U
R
S
E
More clues leading to the result CURSE
- Swear at dogs on top of Everest
- Swear nothing is taken from path
- Swear nothing's missing from racetrack
- Swear, the way things go without love
- Swear at dog, tips of sausages eaten
- Offensive language recurs excessively? Not completely!
- Swear by remedy containing sulphur
- Scoundrel, oddly withdrawn, is yet to swear
- Medicine containing sulphur is a disaster
- Scout risked regularly to swear
Buddy explains!

The straight part
We know that "Offensive language" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case offensive language = curse.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 CURSE mean?
CURSE noun- A supernatural detriment or hindrance; a bane.
- A prayer or imprecation that harm may befall someone.
- The cause of great harm, evil, or misfortune; that which brings evil or severe affliction; torment.
- A vulgar epithet.
- (usually with "the") A woman's menses.
- To place a curse upon (a person or object).
- To call upon divine or supernatural power to send injury upon; to imprecate evil upon; to execrate.
- To speak or shout a vulgar curse or epithet.
- To use offensive or morally inappropriate language.
- To bring great evil upon; to be the cause of serious harm or unhappiness to; to furnish with that which will be a cause of deep trouble; to afflict or injure grievously; to harass or torment.