A very detailed definition that I rather like comes from the Crossfit Journal. If you have never heard of Crossfit, they are insane and I love them, so you will hear more about the program. Feel free to check it out at www.crossfit.com
In their introductory journal article they have a very long and detailed definition of various aspects which should be considered under fitness which I recommend reading. However, these are summarised into ten points.
"GENERAL PHYSICAL SKILLS
If your goal is optimum physical competence then all the general physical skills must be considered:
1. Cardiovascular/respiratory endurance - The ability of body systems to gather, process, and deliver oxygen.
2. Stamina - The ability of body systems to process, deliver, store, and utilize energy.
3. Strength - The ability of a muscular unit, or combination of muscular units, to apply force.
4. Flexibility - the ability to maximize the range of motion at a given joint.
5. Power - The ability of a muscular unit, or combination of muscular units, to apply maximum force in minimum time.
6. Speed - The ability to minimize the time cycle of a repeated movement.
7. Coordination - The ability to combine several distinct movement patterns into a singular distinct movement.
8. Agility - The ability to minimize transition time from one movement pattern to another.
9. Balance - The ability to control the placement of the bodies center of gravity in relation to its support base.
10. Accuracy - The ability to control movement in a given direction or at a given intensity."
Having said that, my absolute favourite definition of fitness/laziness comes from Terry Pratchett:
Not simply, ordinarily lazy. Ordinary laziness was merely the absence of effort. Victor had passed through there a long time ago, had gone straight through commonplace idleness and out on the far side. He put more effort into avoiding work than most people put into hard labour...
People who didn't apply themselves to the facts in hand might have thought that Victor Tugelbend would be fat and unhealthy. In fact, he was undoubtedly the most athletically-inclined student in the University. Having to haul around extra poundage was far too much effort, so he saw to it that he never put it on and he kept himself in trim because doing things with decent muscles was far less effort than trying to achieve things with bags of flab.
So, my basic definition of fitness is to be able to do anything required with ease.
The Australian Army measure three things for fitness: push-ups, sit ups and then the infamous beep test (also known as shuttle run) or sometimes a 2.4km run.
You can download an MP3 for the shuttle run from the Defence Force website. There appears also to be some apps for this which could work well but I haven't tried any yet.
Male requirement: 15 Push-ups, 45 Sit-ups, 7.5 Shuttle run score
Female requirement: 8 Push-ups, 45 Sit-ups, 7.5 Shuttle run score
For Special Forces Direct Recruiting Scheme (SFDRS) candidates, the PFA standards are:
Male requirement: 30 Push-ups, 60 Sit-ups, 10.1 Shuttle run score
As you can tell from the above Crossfit definition, this doesn't cover a lot of areas such as flexibility or agility. However, it can be nice to know you are fit enough to get into the army.
I also have downloaded for free an app on my phone (I'm an apple girl, so I don't know if there is an android equivalent) by BUPA (It's an Australian health fund) that starts with a fitness test in four areas: flexibility, balance, core and strength.
Keeping your legs straight, bend from standing to try and touch your toes, being careful of your back.
1 point if you can get just beyond your knees.
2 points if you can get halfway down your shins
3 points if you can get to your ankles
4 points if you can touch your toes.
Stand on one foot with your other leg bent at 90 degrees (like you are about to step up onto a box) for as long as you can. You may use your arms to balance, but cannot hold onto anything.
1 point for 0 seconds
2 points for 5-10seconds
3 points for 15 seconds
4 points for 20+ seconds
The plank test. Start by lying on your front, tuck your toes under and push up onto your forearms. You should aim to maintain a flat spine. Hold it for as long as possible without dropping or raising your hips.
(image stolen from: femalesintraininggym.com, no it's not me, sadly)
1 point for 10 seconds
2 points for 20 seconds
3 points for 40 seconds
4 points for 1+ minutes.
Distance hop test. Measure out 6 meters on a flat area. The aim is to cover the 6ms in as few hops as possible. Hops are on one foot only.
1 point for 7+ hops.
2 Points for 6 hops
3 points for 5 hops
4 points for 4 hops.
Based on these four exercises, BUPA suggest you identify where you need to improve (though this doesn't take into account cardio at all, which the beep test does).
So, try doing both tests and if you are confident, post below your scores.