For more detailed explanations of terminology, kindly refer to the wonderful Coxford Singlish Dictionary. This is only a compilation of terms more frequently heard serving NS, along with NS-contextual descriptions and explanations.
NS - National Slavery
National Service is often described by many as 'National Slavery' as for two wholesome years you are chained to Singapore, neither willing nor able to escape. Going AWOL is not the prudent man's solution, for you will still have to serve your time after you are released from detention barracks. If you want to do it right, rescind Singaporean citizenship and obtain it elsewhere, most preferably in another nation without conscription.
Wayang & The Singapore Acting Foundation
Wayang, translated literally into 'acting', is an essential survival skill for NS. At the most basic level, wayang-ing is to pretend that you are actually working, while in truth you are skiving. In my experience, when you have typical regulars who play with workplace politics for your superiors, there is usually no correlation between doing your work well and getting rewarded for it, like getting off or early book-out. Therefore, it only makes sense to wayang your two years away since there is a limited amount of time served but an unlimited amount of work to finish. Related terms include 'eye power' and 'No Action, Talk Only'
To 'kena arrow(ed)' is to get assigned a task. This is a fundamental concept of NS -- you will either be assigned sai kang (lit. shit work) or will have to do another person's work for him, most of the time. From cleaning toilets to moving crates, getting arrowed is something you should not endevour to achieve.
To be overtly enthusiastic. You should avoid being garang in NS, since other NSFs, or conscripts, will only see you as trying to boot lick. Similarly, regulars will only take advantage of your willingness to work by pushing their work to you.
To move out of the way. Can be used in conjunction with other terms, e.g. 'Siam arrow'.
To disappear at work, usually to a secluded hiding spot. If you are seen less, you will be shot at, with arrows, less often. If you are so unfortunate as to be caught doing this, a plausible excuse such as 'I went to the toilet' or 'I was doing some work' might get you out of trouble, even if the regulars see through them. They've been in the Army for decades now; they've seen their fair share of stunts. However, they usually cannot be bothered with NSFs and they let us go. Of course, apply some common sense here, and if your superior is a savage man-eating, head-smashing bugger, try not to pull stunts too often. Try not to anger the hand which holds your leash. Legendary ninjas, typically experienced regulars, have been known to combine wayang and ninja skills to remain invisible in plain sight. Similarly, 'to throw smoke' is used to the same effect.
Malingering, usually achieved with a polyclinic MC or Medical Officer's excuse letter. Deeply frowned upon by other NSFs, since they will have to pick up the slack you left by leaving. Unless, of course, all your NSF buddies have already chao keng-ed before you even entertained the thought.
To suck it up and resign to fate. If you are unable to escape from the evil the SAF calls 'work', you have to just accept your misfortune. You would never survive NS otherwise.
Lan Lan Suck Thumb
refer Lan Lan
To feel extremely annoyed, with a tinge of anger. Maybe 'pissed off' would be more accurate. Frequently experienced after trying to lan lan suck thumb.