Collocations for defensive - adj.

be

purely
These are purely defensive measures.

essentially, largely
a largely defensive campaign

be, feel, look, seem, sound
become, get, grow
Whenever anyone mentions women's rights, he gets rather defensive.

extremely, fairly, very, etc.
fiercely
He did not once glance at his listeners and seemed fiercely defensive.

a little, slightly, etc.
overly

about
He is extremely defensive about his work.

Defensive is used with these nouns:
alliance, firearm, line, manoeuvre, measure, move, perimeter, play, player, position, posture, shield, stance, strategy, tackle, touchdown, trench