Interactions between Ideal Voltage and Current Sources
There's only one path to consider, so don't worry about neglecting the sources in turn. Instead, just focus first on the current source - since there's only one path it will do its best to dictate the current in the path.

That means there is 2mA flowing into the -ve terminal of the 10V, through the 1kR and back to the current source. Does that mean the voltage source is supplying or absorbing power? Just think of a battery - when it supplies power, current leaves the positive terminal and returns to the negative terminal. That's the same arrangement as we have here, therefore the voltage source is supplying power.

That leaves the current source, for which we need the voltage across it. Going around the circuit counterclock-wise we have +10V due to the voltage source and -2V due to the current flowing through the resistor. That leaves 8V to be dropped across the current source, with the most positive terminal being the top.

Like a battery, a current source will normally deliver current out of its positive terminal and return via its negative terminal. In this case the opposite is true, therefore it is absorbing power.