I'm trying to express in which conditions alarms do occur and can't decide which term would sound more official/technical in a technical manual.

Which one sounds better (or is there another better suiting term):

"Alarms occur when ... which obstruct the operation of the machine."
"Alarms occur when ... which hinder the operation of the machine."

5 Answers 5


Obstruct is a synonym of hinder:

  • As verbs the difference between obstruct and hinder is that obstruct is to block or fill (a passage) with obstacles or an obstacle see synonyms at block while hinder is to make difficult to accomplish; to frustrate, act as obstacle.

Ngram (hinder/obstruct the operation). The examples shown don't refer only to mechanical devices but I think that they suggest that the two terms are used as synonyms.

  • I think that they both may well be used in a technical context.
  • Thanks for the fast and informative answer. I'll be more relieved while choosing one of them.
    – Montag451
    Mar 31, 2015 at 14:40

The term obstruct gives us the idea that the flow of an action is blocked so then in terms of a technical manual, it would seem a better fit for the context. A technical manual describes how a particular thing works, therefore that idea of action is reinforced by the obstruction of the regular actions of a piece of machinery.


This is difficult to answer because you do not give us the complete sentence.

"Alarms occur when ... which obstruct the operation of the machine."

As written, the sentence seems to imply that the "alarms" affect the operation of the machine. This is because we have no knowledge of what the "..." represents. Also the verb - obstruct - and not - obstructs - implies a plural subject.

However the sentence could be:

Alarms occur when the filter plugs which obstructs the operation of the machine.

Here the alarms are simply a warning that something is wrong. It is the filter that is the problem.

So without knowing the composition of the "when" clause it is impossible to answer your question as to which word is better.


Because both of them allow multiple meanings, sometimes I would avoid either of them, and I'd use their more limited-meaning/specialized synonyms: say block up, retard, check, impede, make slow, impair, damage

See those synonyms indicated in their very definitions e.g.:


verb transitive

1 obsolete : to do harm to : impair, damage

2 : to make slow or difficult the course or progress of : retard, hamper

3 : to keep from occurring, starting, or continuing : hold back : prevent, check — often used with from

4 : to interfere with the activity of (a group or molecule of a compound) especially as a result of space relationships — compare block 1g, steric hindrance

Merriam-Webster Unabridged Dictionary

Also, consult the best source, bar none, for synonym separation:

Merriam-Webster's Dictionary of Synonyms: A Dictionary of Discriminated ... p. 402 Compare "hinder" and "obstruct" there.


When we use "obstruct" we think of an obstruction, usually something physical, doing the obstructing. To hinder on the other hand is a verb less bound to the idea of some object.

His weariness hindered his stride, the boulders obstructed his path, his clothing hampered his movements... his situation was alarming.

We would have to know the nature of the spanner in the works, or which ill wind blows, or whatever is causing the problem, in order to select the best word.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.