彼の退職は会社にとって大きな失だ。
His resignation is a great loss for the company.
There was a flaw in the plan.
He admitted his mistake.
The shortstop was charged with an error.
失敗 is the standard everyday word for a failure or mistake, while 失 is a more formal term often confined to written or specialized language.
欠点 is the common word for a flaw or defect, while 失 covers similar ground but is rarer and more formal.
失策 is the full word for a blunder or error, including baseball errors, while 失 is its abbreviated form used especially in baseball scorekeeping.
The kanji 失 means 'lose, error, fault'. The reading しつ is the on'yomi. The word is used as a formal noun in modern Japanese, likely derived from classical Chinese usage.
disappearance; vanishing; loss
negligent error; blunder; accident caused by negligence · fault; defect; culpability
unrequited love; broken heart; disappointment in love
loss; going missing; misplacement
imbalance; disharmony; malfunction · ataxia
fainting; losing consciousness; passing out · syncope
blunder; disgrace; failure
stall; lose airspeed · downturn; slowdown; slump; decline
fall from power; downfall; losing one's position
loss of eyesight; blindness
incontinence; involuntary urination/defecation
lapse; expiration; invalidation; becoming void
blunder; slip; error · error (baseball)
destruction by fire; being burnt down
verbal gaffe; slip of the tongue; improper remark
involuntary laughter; laughing despite oneself · scornful laughter; snicker
disappointment; despair; despondency
forgetting; lapse of memory
rudeness; impoliteness; disrespect · leaving; taking one's leave · taking without permission; stealing; pinching · sorry!; excuse me!; I'm off!
wash away; be carried off; loss by water
losing one's job; unemployment