detrimental (to)

harmful; damaging

the sun's detrimental effect on skin

The policy will be detrimental to the peace process.

mug

to attack and rob somebody, especially a pedestrian in a public place

She had been mugged in the street in broad daylight.

rich

containing/providing something

Oranges are rich in vitamin C.

The area is rich in wildlife.

whisper

to murmur

Don't you know it's rude to whisper?

She leaned over and whispered something in his ear.

He whispered to me that he was afraid.

behave

to act; to do things in a particular way

The doctor behaved very unprofessionally.

They behaved very badly towards their guests.

He behaved like a true gentleman.

She behaved with great dignity.

loyal (to somebody/something)

true; remaining faithful to somebody/something and supporting them or it

a loyal friend/supporter

She has always remained loyal to her political principles.

in accord with
(formal) in agreement with

This action would not be in accord with our policy.

Botanists are not in complete accord about how many species exist. 

surplus

more than is needed

The world is now producing large food surpluses.

The government has authorized the army to sell its surplus weapons.

Wheat was in surplus that year.

The store is selling off stock that is surplus to requirements (= more than they need to have). 

fountainhead

a source or origin

He is the fountainhead of all that is holy and sacred in the universe.

in so far as

to the degree that

That's the truth, in so far as I know it.

gainful

(of employment) paid

a gainful occupation

gainful employment

spectrum

a range of opinions, feelings, etc.

He has support from across the whole political spectrum.

A wide spectrum of opinion was represented at the meeting.

time enough

There'll be time enough to relax when you've finished your work.

participant (in something)

participator; a person who is taking part in an activity or event

He has been an active participant in the discussion.

oath

solemn declaration naming God etc. as witness

to take/swear an oath of allegiance

All members had to swear a solemn oath never to reveal the secrets of the organization.

You are bound by oath to tell the truth.