Difference between Sampajanna and Vipassana If Sampajanna is clear comprehension and Vipassana is clearly seeing how or are they distinguishable?
Sampajanna is a prerequisite for right concentration. Vipassana is a result of right concentration.
Mindfulness &gt; sampajanna &gt; concentration &gt; vipassana &gt; liberation &gt; nibbana
Sampajanna is a product of active volition &amp; mindfulness; what is called 'wise or careful attention' (yoni­so­ma­nasikāro); as described in AN 10.61:

Mindfulness and clear comprehension, too, I say, have a nutriment; they are not without nutriment. And what is the nutriment for mindfulness and clear comprehension? It should be said: careful attention (yoni­so­ma­nasikāro). AN 10.61

Vipassana is the automatic seeing of ultimate truth that occurs when the mind is clear &amp; concentrated, as described in AN 11.2.

For a person whose mind is concentrated, there is no need for an act of will, 'May I know &amp; see things as they actually are.' It is in the nature of things that a person whose mind is concentrated knows &amp; sees things as they actually are. AN 11.2

Sampajanna (applied wisdom) is the preliminary wisdom that mindfulness (remembering; recollection) brings to mind to establish meditation. Again, to quote AN 10.61:

The four establishments of mindfulness, too, I say, have a nutriment; they are not without nutriment. And what is the nutriment for the four establishments of mindfulness? It should be said: ... mindfulness and clear comprehension. AN 10.61

For example, when meditation is established, sampajanna applies the types of wisdoms listed below, when required:

observing breathing brings peace therefore it is beneficial to observe the breathing

craving &amp; attachment cause suffering &amp; disturbances therefore I should meditate without craving &amp; attachment

this hindrance harms myself &amp; harms another therefore it should be abandoned


Bhikkhu Buddhadasa has explained 'sampajanna' &amp; 'vipassana' below:

sampajanna, wisdom-in-action, ready comprehension, clear comprehension: the specific application of  panna as required in a
given situation.
vipassana, insight: literally, &quot;clear seeing,&quot; to see clearly, distinctly, directly into the true nature of  things, into
aniccam-dukkham-anatta. Vipassana is popularly used for mental
development practiced for the sake of true insight. In such cases, the
physical posture, theory, and method of such practices must not be
confused with true realization of impermanence, unsatisfactori­ness,
and not-self. Vipassana cannot be taught.
SAMPAJAÑÑA
Sampajanna is wisdom as it meets up with and immediately confronts a problem, as it deals with and wipes
out that problem -- this is wisdom-in-action. It is only that wisdom
specifically related and applied to a particular situation or event.
The word &quot;wisdom&quot; (paññä) encompasses many
meanings and understandings, we can't even begin to estimate its
content. However, the word &quot;sampajanna&quot; is far more limited in its
meaning. It is exactly that wisdom directly needed for the problem
that confronts us. Active wisdom isn't general, it is a matter of
particulars.
We can compare wisdom (paññä) with the medicine chest in our house. In it we store a wide variety of drugs, pills, capsules, ointments, powders,
and syrups for possible use. When we're actually sick, we must choose
from among the many the one drug which will be effective in treating
our ailment. We can't take them all; we take just what is needed to
cure our illness here and now. The same is true for wisdom. Understand
that there's an incredible amount of what we call paññä,
but that we only apply a little bit at a time. We apply just that
portion which can take care of the immediate situation. Know how to
use the Dhamma, the paññä, which is exactly relevant to our situation
and problem. The Dhamma or wisdom which controls that situation and
problem is what we call &quot;sampajanna.&quot;
The Scientific Cure of Spiritual Disease