Dictionaries will become major offensive and defensive weapons of the future in skirmishes between federal chiefs and employes they want to dislodge from governments jobs.

The books, ranging from baby pocket-sized models to the giants on library shelves, will be added to the arsenals of personnel offices, legal sections, union representatives and employe's battle gear.

They will not replace conventionals weapons like administrative decisions, tons of regulations and other items now standard in U.S. firing cases. The president's civil service reforms will give new, important meanings to word definition. No combatant worth his or her salt will want to be without several authoritative dictionaries.

President Carter's civil service reform package is about to become law. Senate-House conferees, barring a filibuster or a walkout, will put the final stamp of approval on the bill early next week. Part of the reform is designed to make it easier for the government to fire marginal workers - something the White House believes is now too difficult to do.

Both backers and opponents of civil service reform agree that it will be easier in the future for Uncle Sam to take quick, positive action against workers who are either incompetent or who misbehave badly on the job. And also against those who are none of the above.

At the Senate-House compromise session yesterday, the two sides agreed to language that is supposed to spell out what it will take to sack a civil servant. That is where the dictionaries will come in.

The two areas the Senate House bill writers dealt with yesterday concern "adverse actions." That is bureaucratic term for firing, canning, or dumping someone who works for the government.

On Thursday the conferees agreed that the government must have "substantial" evidence to justify firing a government worker for poor performance. They also agreed that, in the case of misconduct, there must be a "preponderance" of evidence before an employe can be given the government version of a pink slip.

Granted it isn't easy to write language dealing with the very traumatic business of firing someone. So the senators and congressmen had their work cut for them trying to give management what it says it needs, while trying to give federal workers a fair shake and some protection against arbitrary, unfair or politically motivated firings.

To that end, the conference committee members agreed there must be a "substantial" level of evidence in adverse actions dealing with performance-related dismissals, and the requirement of a "preponderance" of evidence in misconduct cases. Asked what those terms meant, one conferee said there are "easily 19 different definitions for each word." He predicted there might be 1,900 differences once the new system gets rolling.

In effect, the conference member said it would be easier to fire someone for poor performance, under the "substantial" definitions than it will be to get a "preponderance" of evidence for misconduct cases.

This means that in the future a lot of federal workers - innocents and incompetents, good guys and rowdies - will lose or hold on their jobs based on the definition of the words "substantial" and "preponderance." Unless both labor and management can agree on definitions - an unlikely prospect - or at least use the same dictionaries, it may take a new act of Congress to explain this recent act of Congress.

Convention Charity: Delegates to the National League of Postmasters made on-the-spot cash donations to delegate Arnaldo A. Rovinelli, a Texas delegate who suffered a heart attack. The league also let the delegate and his family use its apartment until he was well enough to return home.

Government Information Programs: American University has set up a special institute to study everything the government produces in the information field. The project, a joint venture with the National Association of Government Communicators, will analyze wht Uncle Sam is doing right and wrong.

But most important, it hopes to fix a handle on what the government is doing in information areas.

AU's Ken Rabin will head the institute. Wesley Pedersen of the International Communications Agency (formerly the USIA) is credited with coming up with the idea for the institute, and for nagging the powers-that-be to get it rolling.