spark /spɑːrk/
1 a small fiery particle thrown off from a fire, alight in ashes, or produced by striking together two hard surfaces such as stone or metal.
• a small flash of light produced by a sudden disruptive electrical discharge through the air:
there was a spark of light.
• an electrical discharge serving to ignite the explosive mixture in an internal combustion engine.
2 a trace of a specified quality or intense feeling:
a tiny spark of anger flared within her.
• a sense of liveliness and excitement: there was a spark between them at their first meeting.
1 [no object] emit
sparks of fire or electricity: the ignition sparks as soon as the gas is turned on.
• produce
sparks at the point where an electric circuit is interrupted.
2 [with object] ignite:
the explosion sparked a fire.
• provide the stimulus for (a dramatic event or process): the severity of the plan sparked off street protests.

sparks fly
an encounter becomes heated or lively: sparks always fly when you two get together.

spark /spɑːrk/
a spark of light: FLASH, glint, twinkle, flicker, flare, pinprick.
not a spark of truth in the story: PARTICLE, iota, jot, whit, glimmer, atom, bit, trace, vestige, ounce, shred, crumb, grain, mite, hint, touch, suggestion, whisper, scintilla; informal smidgen, tad.
the trial sparked a furious debate: CAUSE, give rise to, lead to, occasion, bring about, start, initiate, precipitate, prompt, trigger (off), provoke, stimulate, stir up.

1 a sin in the eyes of God: IMMORAL ACT, wrong, wrongdoing, act of evil/wickedness, transgression, crime, offense, misdeed, misdemeanor; archaic trespass.
the human capacity for sin: WICKEDNESS, wrongdoing, wrong, evil, evildoing, sinfulness, immorality, iniquity, vice, crime. ANTONYMS virtue.
3 informal
they've cut the school music program—it's a sin: scandal, crime, disgrace, outrage.

I have sinned: COMMIT A SIN, commit an offense, transgress, do wrong, commit a crime, break the law, misbehave, go astray; archaic trespass.

Old English
synn (noun), syngian (verb); probably related to Latin sons, sont- ‘guilty’.

Choose the right word

sin, crime, fault, indiscretion, offense, transgression, vice

If you've ever driven through a red light or chewed with your mouth open, you've committed an
offense, which is a broad term covering any violation of the law or of standards of propriety and taste. A sin, on the other hand, is an act that specifically violates a religious, ethical, or moral standard (to marry someone of another faith was considered a sin). Transgression is a weightier and more serious word for sin, suggesting any violation of an agreed-upon set of rules (their behavior was clearly a transgression of the terms set forth in the treaty). A crime is any act forbidden by law and punishable upon conviction (a crime for which he was sentenced to death). A vice has less to do with violating the law and more to do with habits and practices that debase a person's character (alcohol was her only vice). Fault and indiscretion are gentler words, although they may be used as euphemisms for sin or crime. A fault is an unsatisfactory feature in someone's character (she is exuberant to a fault), while indiscretion refers to an unwise or improper action (speaking to the media was an indiscretion for which she was chastised). In recent years, however, indiscretion has become a euphemism for such sins as adultery, as if to excuse such behavior by attributing it to a momentary lapse of judgment (his indiscretions were no secret).