Is lack of confidence, laziness?

American ... team spirit could be applicable in sports, work or various other situations...and it doesn't necessarily have to do with self confidence....because self confidence is between YOUR ears. 
 

There are a few reasons for lack of confidence...I don't really think it's laziness. 

One could be your upbringing.... being told you no good, stupid, or a screw up... etc.
Another could be failure.... and not knowing how to overcome that.
 
Not knowing enough about a particular subject....knowledge brings confidence.

Getting shot down, mocked, ridiculed or harassed by your piers.

One or all those things can slowly chip away at confidence and cause you to pull back and become self-conscious.

**For me knowing who I am and what I am in Christ allows me to walk fully persuaded that I am equal to anything and ready for anything ..."I can do all things through Christ who strengthens me"!     

A lack of confidence comes from a deeper source within us than just being "not brave."   It's often the result of environmental upbringing or abuse which eats away at our core, leaving us with a lack of self assurance, even if we have the ability to counter its effects.

No that would be cowardice 

Sadness is laziness.

The two are related in the sense that in order to lack confidence, you have to have a poor outlook on yourself thereby recognizing that you make no effort to be a better person.  In order to have confidence, you need to work on your character (honesty, responsibility, integrity, self-control, etc.).  Once you have achieved good character, your confidence will appear out of thin air.  In addition, you need to develop your individual knowledge, skills, and abilities to build on your character.  It takes time and effort--both of which everyone possesses.   

More like a lack of  courage.

No, noway for you to compare lack of confidence with laziness.