follow through (on (something))

to continue something until it is completed.

It was an unpopular idea, but he followed through on it anyway.

I am sorry now that I didn't follow through with music lessons when I was younger.

Etymology: based on the sports meaning of follow through (= to continue the movement of a swing, even after hitting a ball)

• nearly jump out of your skin
• near miss
• necessary evil
• Necessity is the mother of invention.
• neck and neck
• neck of the woods
• need head examined
• need head examining
• need I say more
• needle in a haystack
• needless to say
• need like a hole in the head
• need like need a hole in the head
• need like you need a hole in the head
• needs must
• need something like a hole in the head
• need something like need a hole in the head
• need something like you need a hole in the head
• need to have head examined
• need to have your head examined
• need your head examined
• need your head examining
• neither here nor there
• nerves of steel
• nest egg