Odd !
The opposite of an even number is an odd number.
The opposite of odd is even. If you divide a even or odd number with odd, you will still get a fraction, or a romander.
It's opposite is a negative. :P
even number
working even harder
The opposite word of space is crowded. Or even cramped would work.
The opposite of elusive (evasive) could be confronting or even enticing. The opposite of elusive (difficult to perceive) would be obvious, clear, or simple.
The answer depends on where opposite! Even if you could spell correctly, the answer would depend on whether you meant the additive opposite or the multiplicative opposite.
The opposite of friendly is "unfriendly" but you can also use aloof, stand-offish, or even unwelcoming.
A line through the vertex and the side opposite - nothing more. There need not even be a side opposite - as is the case with a square!
The opposite of somewhere (unspecified location) could be nowhere, or it could be here (opposite of (somewhere else or there), or even there. (a specified location).
unswered is a word, it is the opposite of answered