temerity

If you have the temerity to jump off the bridge even after hearing about the risk of instant death, you truly are a fool. 

 iota 

As far as science is concerned, there is not one iota of evidence to prove that life exists on other planets.

elucidate

• She read everything she could get her hands on that would elucidate and expand upon her study of the human brain. 

to make understood, to clarify, to shed light upon something.

(elucidated, elucidating, elucidates)

expunge 

The judge directed the court stenographer to expunge the last three paragraphs of witness's testimony because she was hysterical.

to strike or blot something out; erase; obliterate.

(expunged, expunging, expunges)

 gait 

We had slowed to a cautious gait and were feeling our way forward so as not to bump into the trees.

purloin 

Jeremy must have purloined a copy of the school's master key because that is the only way he could have gotten into the cafeteria without breaking a window. 

to steal something.

 (purloined, purloins, purloining) 

capacious

That mini-van has a capacious storage area which makes it an ideal choice for larger families.

containing or capable of containing a large amount of something.

(capacity, capaciously, capaciousness)

 trepidation 

After listening to the teacher describe how important the NYS ELA test was and all the preparation needed to do well on the test, Pam began to feel her trepidation grow about failing the assessment. 

 a feeling of fear that causes you to hesitate because you think something bad or unpleasant is going to happen.

(trepid, trepidly, trepidity, trepidant, intrepid) 

irascible

Unlike his twin brother who never seems to get upset, Colin is irascible and gets angry very quickly.

becoming angry very easily : having a bad temper.

(irascibility, irascibly, irascibleness)  

pithy

using few words in a clever and effective way.

(pithier, pithiest)