Theory:

Meaning of difficult words from the lesson "Quality":
 
S.No
Words
Meaning
1.
By-street A side street or lane
2.
Mysterious A strange thing that one cannot understand
3.
EssenceThe basic or most important feature of something
4.
Fashionable placePopular place with rich people
5.
DistinctionDifference
6.
Reliant onDepending on
7.
Handiwork Something impressive that someone has done
8.
Awestruck Feeling very impressed by something
9.
AwfullyTerribly
10.
Guttural soundA deep sound produced from the throat
11.
Ambience The atmosphere of a place
12.
RemarksAn opinion or judgement
13.
EssenceThe most important feature or quality of something
14.
Dedication The hard work and efficiency that someone puts into an activity or a work
15.
Unique Being the only one of its type
16.
ApronA piece of cloth worn over the front of the body
17.
IncenseA substance that produced a pleasant smell
18.
FortnightFourteen days
19.
Retiring Preferring not to spend time with others
20.
Whence From where
21.
Inhale To breathe in
22.
ConvenientSuited to your preferences or needs
23.
Outset From the beginning
24.
CreakyWorn and broken by hard use
25.
Defective Imperfect or faulty
26.
IrreparableThat cannot be repaired
27.
QualifyModify
28.
Absent-mindedBeing lost in one's thoughts and inattentive to one's surroundings.
29.
Penetrate/pierceTo pass into or through 
30.
ExamineCheck out carefully
31.
ContemptLack of respect
32.
BitterlyIn a way that shows you feel angry or disappointed
33.
WrinkleA line that emerges on the skin when you become older
34.
HardshipA situation that causes difficulty or suffering
35.
Ill-omenedSomething that appears to be unlucky
36.
CircumstanceA fact or occurrence that influences a situation
37.
MistookTo identify wrongly
38.
PeerTo look closely or carefully at something
39.
WanLooking pale and weak
40.
RetainTo hold/keep someone or something 
41.
MurmurTo say something in a quiet voice
42.
AppealA characteristic of anything that causes people to like or desire it
43.
PinchedTired, skinny and ill in appearance
44.
WornLooking tired and worn
45.
SlackNot busy
46.
AnxietyA feeling of worry or unpleasant emotion
47.
Splendidly Excellent
48.
AmissWrong
49.
WorkaholicA person who enjoys working and works excessively
50.
StarvationTo die from lack of food
51.
ExaggerateTo make anything appear larger, better, or worse than it is
52.
FloweryNot expressed in a clear or simple way