Jude 1:23 about unclean clothing.
Jud 1:22 And have mercy on some who are wavering;
Jud 1:23 save others by snatching them out of the fire; and have mercy on still others with fear, hating even the tunic defiled by their bodies.
Jud 1:22 And haveG1653 mercyG1653 on someG3739 G3303a, who are doubtingG1252;
Jud 1:23 saveG4982 others, snatchingG726 them out of the fireG4442; and on someG3739 haveG1653 mercyG1653 with fearG5401, hatingG3404 evenG2532 the garmentG5509 pollutedG4695 by the fleshG4561.
NRSV/NAS with Strong's.
G4695
σπιλόω
spiloō
Thayer Definition:
1) to defile, spot
Not talking about stains or sex sin anywhere in that verse. Your interpretation reads too much information into that passage to be realistic.
Fornication is adultery and sex sin outside marriage.
Fornication, biblically, are forbidden sex acts. Adultery is sex between a married person and someone who is not their spouse whether that person be married or unmarried. The two are not the same.
G4202
πορνεία
porneia
Thayer Definition:
1) illicit sexual intercourse
1a) adultery, fornication, homosexuality, lesbianism, intercourse with animals etc.
1b) sexual intercourse with close relatives; Lev. 18
1c) sexual intercourse with a divorced man or woman; Mar_10:11,Mar_10:12
2) metaphorically the worship of idols
2a) of the defilement of idolatry, as incurred by eating the sacrifices offered to idols
Part of Speech: noun feminine
G3431
μοιχεύω
moicheuō
Thayer Definition:
1) to commit adultery
1a) to be an adulterer
1b) to commit adultery with, have unlawful intercourse with anothers wife
1c) of the wife: to suffer adultery, be debauched
1d) A Hebrew idiom, the word is used of those who at a womans solicitation are drawn away to idolatry, i.e. to the eating of things sacrificed to idols
Part of Speech: verb
Lust I defined earlier, inordinate desire to have and enjoy. From the dictionary.
Which dictionary? English, Greek, or Hebrew?
Your definition, if applied to Matthew 5, means one of two things:
Married people lust and in so doing sin.
Lust can be sinful or not sinful.
Either way, you do not have a case for masturbation being condemned. The first is nonsensical, and the second is so vague that the definition is essentially useless.
Your definition also raises other issues. Why is it a sin to enjoy something a lot? What about masturbation involves an inordinate desire?
adj.
- Exceeding reasonable limits; immoderate. See synonyms at excessive.
- Not regulated; disorderly.
Read more: inordinate: Definition, Synonyms from Answers.com
In order for you to say it's inordinate, you would need to prove that the desires accompanying masturbation are unusually strong or unregulated. Given that most guys touch, you'll have a hard time making that case.
Your definition, then, applied to the issue of masturbation, is actually unrelated to most masturbation.
I doubt the definition you've provided is fully accurate to the Greek, but it captures the gist of it.
http://students.eng.fiu.edu/~denver/pdfs/Masturbation.pdf
The preceding article explains what lust is and why masturbation is unrelated to it.