Theory:

Meaning of difficult words from the lesson "The Mystery of the Cyber Friend":
 
S.No
Words
Meaning
1.
Stuff  
To fill something in something 
 2. 
Delicious
Having a pleasant taste or smell
3.
Fond Liking something
4.
Nap
To sleep for a short time
5.
AddictDoing something regularly as a habit
6.
Flavour
A particular type of taste
7.
Leisure
Free time
8.
Ping
To send an email or text message
9.
BlockTo stop
10.
Regret To feel sorry about something
11.
Embarrass To make somebody feel uncomfortable, ashamed, shy etc..
12.
Ignore
To pay no attention to something
13.
Sign off
To conclude
14.
PuzzleSomething that is difficult to understand
15.
IntimacyA close personal relationship
16.
Delight
Great pleasure or joy
17.
Recall
To remember something
18.
SkipTo not do something that you usually do 
19.
PermitTo allow
20.
Gradually Slowly
21.
Awe-inspiring
Very impressive
22.
Prompt
To cause something to happen
23.
Adoring Showing great love and admiration
24.
Snap
Photograph
25.
Impact
An effect or an influence
26.
Arrive
To reach a place
27.
ShroudTo cover or hide something
28.
Look overTo examine something quickly
29.
InsistTo keep saying very firmly that something is true
30.
HecticVery busy with full of activity
31.
Fascinated
Attracted or interested toward something
32.
Persuade To make someone do or believe something
33.
Furious Extremely angry
34.
Strange
Something unusual or unexpected
35.
LyingTelling untruthful things
36.
Recall
To remember something
37.
SuspicionA feeling or belief that something is wrong
38.
PervadeTo spread through the whole of something
39.
Accompany
To go together with somebody or something
40.
Junction
A place where roads, railway lines, etc. meet.
41.
Unfortunately
Unluckily
42.
StareTo look at something steadily for a long time 
43.
ApproachTo move towards
44.
StutterTo speak with difficulty and repeating words
45.
ShriekA high pitched voice
46.
TolerateTo allow something that you do not like
47.
BefriendTo become the friend of someone
48.
Trap
To keep someone in a dangerous situation so that he/she cannot escape
49.
Yell
To shout loudly when you angry, feared or in pain
50.
Niece
The daughter of your brother or sister/the daughter of your wife (or) husband's brother or sister
51.
RushTo move with a great speed
52.
Disappear To become impossible to see
53.
DeceiveTo make someone believe something that is not true
54.
Imposter
A person who pretends to be somebody else to trick people
55.
Confide
To tell someone secrets and personal information
56.
Pretend
To behave in a particular way to make people believe something is true when it is not
57.
NabTo catch and arrest someone who is doing a wrong thing
58.
AssistTo help someone
59.
BefriendTo become a friend of someone
60.
Adventure An unusual, dangerous, exciting experience
61.
RestrictTo stop or control something
62.
VowTo make a serious promise
63.
OffenderA person who commits a crime
64.
ExamineTo look at something/somebody carefully in order to find out something
65.
BefriendTo become the friend of someone
66.
Blue-collar jobs Jobs involving manual labor