Adolescence /ˌæd

relevance /ˈrel.ə.v ə n t  s/ noun [ U ] ( also relevancy )
the degree to which something is related or useful to what is happening or being talked about
What relevance does that point have to the discussion?
Opposite irrelevance
safeguard /ˈseɪf.gɑːd/ /-gɑːrd/ verb [ T ]
to protect something from harm
The union safeguards the interests of all its members.
safeguard noun [ C or U ]
The disk has built-in safeguards to prevent certain errors.
safeguard against sth phrasal verb
to do things that you hope will stop something unpleasant from happening
A good diet will safeguard against disease.
source /sɔːs/ /sɔːrs/ noun [ C ]
1. the place something comes from or starts at, or the cause of something
a source of heat/energy/light
a heat/energy/light source
Oranges are a good source of vitamin C.
Experts are trying to track down the source of the contamination in the water supply.
We walked up the river to its source in the hills.
Money is often a source of tension and disagreements in young married couples.
2. someone or something that supplies information
The journalist refused to reveal her sources (= say who had given the information to her) .
According to Government sources (= people in the Government) many MPs are worried about this issue.
Always acknowledge your sources (= say which books you have used) at the end of an essay.
3. at source
at the place where something comes from
Tax is deducted from my income at source.