These ROOT-WORDS are JAC, JEC & JECT meaning THROW & LIE. An oddity about this ROOT is that it never stands alone, as other ROOTS do. Standing alone, it has no meaning. It is entirely dependent on prefixes and suffixes to be meaningful.
1. Dejected : de JECT ed (de jekt’ ed) adj.
Low in spirits; cast down
2. Dejection : de JECT ion (de jek’ shun) n.
A condition of despair; depression
3. Adjacent : ad JAC ent (ad jas’ ent) adj.
Next to; as, the adjacent house
4. Adject : ad JECT (a jekt’) v.
To add to; to annex
5. Adjective : ad JECT ive (aj’ ek tiv) n.
Not standing alone; a word which modifies a noun
6. Adjectival : ad JECT ival (aj ek tie’ val) adj.
Using many adjectives; as, an adjectival style
7. Conject : conJECT (kon jekt’) v.
To plan; to surmise
8. Conjecture : con JECT ure (kon jek’ chur) v.
To form an opinion; to surmise
9. Ejaculate : e JAC ulate (e jak’ yu late) v.
To throw out; cry out
10. Eject : e JECT (e jekt) v.
To throw out; as, eject him from the hall
11. Ejection : e JECT ion (e jek’ shun) n.
The throwing out; expulsion
12. Inject : in JECT (in jekt’) v.
To insert; as, inject a syringe
13. Injection : in JECT ion (in jek’ shun) n.
The throwing in of liquid by a syringe
14. Interjection : inter JECT ion (int er jek’ shun) n.
A word thrown between others; as, He went, alas! To die